NHTSA Tire Fuel Efficiency Consumer Information Program Development

DOT HS 811 154 August 2009

NHTSA Tire Fuel Efficiency Consumer Information Program Development Phase 2 ndash Effects of Tire Rolling Resistance Levels on Traction Treadwear and Vehicle Fuel Economy

This document is available to the public from the National Technical Information Service Springfield Virginia 22161

This publication is distributed by the US Department of Transportation National Highway TrafficSafetyAdministration in the interestof informationexchangeTheopinionsfindingsand conclusions expressed in this publication are those of the author(s) and not necessarily those of the Department of Transportation or the National Highway Traffic Safety Administration The United States Government assumes no liability for its content or use thereof If trade or manufacturersrsquo names or products are mentioned it is because they are considered essential to the object of the publication and should not be construed as an endorsement The United States Government does not endorse products or manufacturers

TECHNICAL REPORT DOCUMENTATION PAGE 1 Report No

DOT HS 811 154 2 Government Accession No 3 Recipients Catalog No

4 Title and Subtitle

5 Report Date

August 2009 6 Performing Organization Code

7 Author(s)

Larry R Evans1 James D MacIsaac Jr2 John R Harris1 Kenneth Yates2 Walter Dudek1 Jason Holmes1 Dr James Popio3 Doug Rice3 Dr M Kamel Salaani1

1Transportation Research Center Inc 2National Highway Traffic Safety Administrashytion 3Smithers Scientific Services Inc

8 Performing Organization Report No

9 Performing Organization Name and Address

National Highway Traffic Safety Administration Vehicle Research and Test Center PO Box B-37 10820 State Route 347 East Liberty OH 43319-0337

10 Work Unit No (TRAIS)

11 Contract or Grant No

DTNH22-03-D-08660 DTNH22-07-D-00060

12 Sponsoring Agency Name and Address

National Highway Traffic Safety Administration 1200 New Jersey Avenue SE Washington DC 20590

13 Type of Report and Period Covered

Final 14 Sponsoring Agency Code

NHTSANVS-312 15 Supplementary Notes

Project support and testing services provided by NHTSA San Angelo Test Facility Akron Rubber Development Laboratory Inc Smithers Scientific Services Inc Standards Testing Laboratories Inc and Transportation Research Center Inc 16 Abstract

This report summarizes the second phase of the project to develop a tire fuel efficiency consumer information program intended to examine possible correlations between tire rolling resistance levels and service variables such as vehicle fuel economy wet and dry traction and outdoor and indoor treadwear Tires of 15 different models with known rolling resistances were installed on the same new passenger car to evaluate their effects of on vehicle fuel economy A 10shypercent decrease in tire rolling resistance resulted in an approximately 11-percent increase in fuel economy for the vehicle This result was within the range predicted by technical literature Reducing the inflation pressure by 25 percent resulted in a small but statistically significant decrease of approximately 03 to 05 miles per gallon for four of the five fuel economy cycles excluding the high-speed high-acceleration US06 cycle This value was smaller than many values predicted by technical literature and possible explanations are being explored

Tires of 16 different models with known rolling resistances were subjected to dry and wet skid-trailer testing on asphalt and concrete skid pads Both the peak (maximum) and slide (fully locked-tire) coefficients of friction were measured and indexed against the control tire For the tires studied there appeared to be no significant relationship between dry peak or slide numbers and rolling resistance However these tire models exhibited a strong and significant relationship between better rolling resistance and poorer wet slide numbers The peak wet slide number displayed the same tendency but the relationship was much weaker This may be significant to consumers without anti-lock braking systems (ABS) on their vehicles since the wet slide value relates most closely to locked-wheel emergency stops For newer vehicles with ABS or electronic stability control systems which operate in the earlier and higher wet peak friction range the tradeoff is less significant For the subset of 5 tire models subjected to on-vehicle treadwear testing (UTQGS) no clear relationship was exhibited between tread wear rate and rolling resistance levels For the subset of 6 tire models subjected to significant amounts of wear in the indoor treadwear tests there was a trend toward faster wear for tires with lower rolling resistance This report concludes with an analysis of the various options in the draft ISO 28580 rolling resistance test and their likelihood of inducing variability in the test results as well as a discussion of data reporting format 17 Key Words

Tire rolling resistance consumer information tire traction Energy Independence and Security Act of 2007 (EISA)

18 Distribution Statement

This report is free of charge from the NHTSA Web site at wwwnhtsadotgov

19 Security Classif (of this report)

Unclassified 20 Security Classif (of this page)

Unclassified 21 No of Pages

153 22 Price

Form DOT F 17007 (8-72) Reproduction of completed page authorized

Approximate Conversions to Metric Measures

Symbol When You Know Multiply by To Find Symbol

LENGTH

in inches 254 centimeters cm ft feet 30 centimeters cm mi miles 16 kilometers km

in2 square inches 65 square centimeters cm2 ft2 square feet 009 square meters m2 mi2 square miles 26 square kilometers km2

MASS (weight)

oz ounces 28 grams g

lb pounds 045 kilograms kg

PRESSURE

psi pounds per inch2 007 bar bar psi pounds per inch2 689 kilopascals kPa

VELOCITY

mph miles per hour 161 kilometers per hour kmh

ACCELERATION

fts2 feet per second2 030 meters per second2 ms2

TEMPERATURE (exact)

F Fahrenheit 59 (Celsius) - 32C Celsius C

Approximate Conversions to English Measures Symbol When You Know Multiply by To Find Symbol

LENGTH

mm millimeters 004 inches in cm centimeters 04 inches in m meters 33 feet ft km kilometers 06 miles mi

cm2 square centimeters 016 square inches in2 km2 square kilometers 04 square miles mi2

MASS (weight)

g grams 0035 ounces ozkg kilograms 22 pounds lb

PRESSURE

bar bar 1450 pounds per inch2 psi kPa kilopascals 0145 pounds per inch2 psi

VELOCITY

kmh kilometers per hour 062 miles per hour mph

ACCELERATION

ms2 meters per second2 328 feet per second2 fts2

TEMPERATURE (exact) C Celsius 95 (Celsius) + 32F Fahrenheit F

TABLE OF CONTENTS 10 INTRODUCTION 1

11 THE CONCEPT OF ROLLING RESISTANCE 3

20 METHODOLOGY 7

21 TEST TIRES 7 211 ASTM F2493 Radial Standard Reference Test Tire 7

22 TIRE ROLLING RESISTANCE TEST PROCEDURES 8 221 ISO Draft International Standard 28580 Single-Point Rolling Resistance 11 222 SAE J1269 amp ISO 18164 Multi-Point Rolling Resistance 11 223 SAE J2452 Multi-Point (Speed Coast Down) Rolling Resistance 11

23 FUEL ECONOMY TEST VEHICLE 11 24 TEST WHEELS 11 25 TEST MATRIX 12 26 TREAD COMPOUND PROPERTIES TESTING 13 27 ON-VEHICLE FUEL ECONOMY TESTING 16

271 EPA 40 CFR Part 86 Dynamometer Fuel Economy Testing 17 28 SKID-TRAILER TIRE TRACTION TESTING 21 29 ON-VEHICLE TIRE TREADWEAR TESTING 23 210 INDOOR TIRE TREADWEAR TESTING 25

30 RESULTS 28

31 EFFECT OF TIRE ROLLING RESISTANCE ON AUTOMOBILE FUEL EFFICIENCY 28 311 Preliminary Analysis Data Shifts 30 312 Highway FET Triplicate Analysis 31 313 Air Conditioning SC03 ndash 112008 to 112508 34 314 Analysis by Date for Possible Drift in Data over Time 35 315 Effect of Tire Rolling Resistance on Fuel Economy 37 316 Effect of Reduced Inflation Pressure on Fuel Economy 43 317 Fuel Economy Testing Summary 50

32 CORRELATION OF TANGENT Δ AT 60degC TO TIRE ROLLING RESISTANCE 51 33 EFFECT OF TIRE ROLLING RESISTANCE ON SAFETY 53

331 Dry Traction Data 53 332 Wet Traction Data 56 333 UTQGS Traction Grade 59 334 Correlation of Tangent δ at 0degC to Wet Traction Properties 61

34 EFFECTS OF TIRE ROLLING RESISTANCE ON TREADWEAR RATE 62 341 Analysis of Wear Data From Indoor Treadwear Testing 65

40 CONCLUSIONS 78

50 REQUIREMENTS 79

60 ROLLING RESISTANCE (Fr) VERSUS ROLLING RESISTANCE COEFICIENT Cr) 85

61 THEORY OF FR AND CR 85 611 Using Cr from a Single-Load Test to Predict Rolling Resistance at Any Load 90

62 DISCUSSION 94

Appendix 1 Tire and Rim Association Inc - Maximum Load Formula for ldquoPrdquo Type Tires 100

Appendix 2 Detailed Test Matrix 101

Appendix 3 Examples of Data Acquired From Indoor Treadwear Test 103

Appendix 4 Raw Dry Traction Testing Results - Asphalt 124

Appendix 5 Raw Dry Traction Testing Results - Concrete 126

Appendix 6 Raw Wet Traction Testing Results - Asphalt 128

Appendix 7 Raw Wet Traction Testing Results - Concrete 130

Appendix 8 UTQG Adjusted Wet Traction Testing Results 132

Appendix 9 ASTM E501 Reference Tire Wet Traction Testing Results 134

Appendix 10 ASTM E501 Reference Tire Dry Traction Testing Results 135

LIST OF FIGURES Figure 1 Where Does the Energy Go 4 Figure 2 Contribution of Tire Rolling Resistance to Vehicle Fuel Economy Versus Speed 5 Figure 3 Magic Triangle Traction Treadwear and Rolling Resistance 6 Figure 4 Force Method Rolling Resistance Test Machine 10 Figure 5 Torque Method Rolling Resistance Test Machine 10 Figure 6 Sample TGA Weight Loss Curve 14 Figure 7 Tan as a Function of Temperature From the Tension Test 15 Figure 8 Tan as a Function of Temperature From the Shear Test 16 Figure 9 Vehicle Fuel Economy Dynamometer Testing 18 Figure 10 NHTSA San Angelo Skid-Trailer 22 Figure 11 UTQGS Treadwear Course 25 Figure 12 Indoor Treadwear Equipment 27 Figure 13 Vehicle Fuel Economy Dynamometer Exhaust Collection Bags and Control System32 Figure 14 Highway FET Schedule Fuel Economy Versus Bag Collection Number 32 Figure 15 Air Conditioning SC03 Fuel Economy Versus Tire Rolling Resistance by Analysis

Group 35 Figure 16 Rolling Resistance of Tires Tested Versus Day of Testing 36 Figure 17 Highway FET (Bag 1) Mileage Versus Tire Rolling Resistance 39 Figure 18 Highway FET (Bag 2) Mileage Versus Tire Rolling Resistance 39 Figure 19 Highway FET (Bag 3) Mileage Versus Tire Rolling Resistance 40 Figure 20 City FTP Mileage Versus Tire Rolling Resistance 40 Figure 21 High Speed US06 Mileage Versus Tire Rolling Resistance 41 Figure 22 Air Conditioning SC03 Mileage Versus Tire Rolling Resistance 41 Figure 23 Cold City FTP Mileage Versus Tire Rolling Resistance 42 Figure 24 Percentage Change in Fuel Economy Versus Percentage Change in 43 Figure 25 Tire to Dynamometer Roller Contact 2008 Chevrolet Impala LS Engine 46 Figure 26 Highway FET (Bag 1) Fuel Economy by Tire Type and Inflation Pressure 47 Figure 27 Highway FET (Bag 2) Fuel Economy by Tire Type and Inflation Pressure 47 Figure 28 Highway FET (Bag 3) Fuel Economy by Tire Type and Inflation Pressure 48 Figure 29 City FTP Fuel Economy by Tire Type and Inflation Pressure 48 Figure 30 High Speed US06 Fuel Economy by Tire Type and Inflation Pressure 49 Figure 31 Air Conditioning SC03 Fuel Economy by Tire Type and Inflation Pressure 49 Figure 32 Cold City FTP Fuel Economy by Tire Type and Inflation Pressure 50 Figure 33 Highway FET (Bag 2) Fuel Economy Versus Tire Rolling Resistance by Tire Type

and Inflation Pressure 51 Figure 34 ISO 28580 Rolling Resistance (lbs)Versus Tangent δ at 60degC by Tire Type 52 Figure 35 Dry Traction Numbers Versus ISO 28580 Rolling Resistance 55 Figure 36 Dry Traction Ratios to E501 Course Monitoring Tire Versus Rolling Resistance 56 Figure 37 Wet Traction Numbers Versus ISO 28580 Rolling Resistance 58 Figure 38 Wet Traction Ratios to E501 Course Monitoring Tire Versus Rolling Resistance 59 Figure 39 UTQG Adjusted Traction Coefficient for Asphalt Versus ISO 28580 Rolling

Resistance 60 Figure 40 UTQG Adjusted Traction Coefficient for Concrete Versus ISO 28580 Rolling

Resistance 61

Figure 41 Slide Traction Number on Wet Concrete Versus Tangent δ at 0degC Measured in Tension 62

Figure 42 Projected Tire Mileage to Wearout (Average and Minimum) Versus ISO 28580 Rolling Resistance 64

Figure 43 Average and Fastest Treadwear Rate Versus ISO 28580 Rolling Resistance 65 Figure 44 Projected Tire Lifetime for Indoor Treadwear Test 67 Figure 45 Treadwear Rate for Indoor Treadwear Test 68 Figure 46 Projected Tire Lifetime for Indoor Treadwear Test 73 Figure 47 ISO 28580 Rolling Resistance Versus Tire Weight Loss 74 Figure 48 Rolling Resistance as Percent of the Original Rolling Resistance 75 Figure 49 Percentage of Original Rolling Resistance 77 Figure 50 Temperature Correction Factor - ISO 28580 83 Figure 51 Drum Diameter Correction Factor - ISO 28580 84 Figure 52 SAE J1269 Recommended Test - Evaluates Response of Rolling Resistance Force

Over a Range of Three Pressures and Two Loads 87 Figure 53 ISO 18164 Annex B - Response of Rolling Resistance Force (Fr) Over a Range of

Three Speeds Two Pressures and Two Loads 88 Figure 54 ISO 28580 Test Conditions for Standard Load Passenger Tires 89 Figure 55 Theoretical Single-Load Rolling Resistance (Fr) 90 Figure 56 Theoretical Single-Load Rolling Resistance Coefficient (Cr) 91 Figure 57 Rolling Resistance of 16 Passenger Tires 92 Figure 58 Rolling Resistance Coefficient of 16 Passenger Tires 93 Figure 59 Rolling Resistance Force (SAE J1269 Single-Point Pounds) 97 Figure 60 Rolling Resistance Coefficient (SAE J1269) 97

LIST OF TABLES Table 1 2005 Motor Vehicle Crash Data From FARS and GES Crashes by Weather Condition 6 Table 2 Phase 2 Tire Models 8 Table 3 Test Matrix 13 Table 4 Analysis of Tread Composition by TGA 14 Table 5 DMA Results for Tangent at 0C and 60C 16 Table 6 2008 EPA Fuel Economy 5-Driving Schedule Test (Source EPA 2009) 19 Table 7 Fuel Economy Test Schedules 21 Table 8 Phase 2 Wet and Dry Skid-Trailer Test Tires 23 Table 9 On-Vehicle Treadwear Testing 24 Table 10 Indoor Treadwear Testing 26 Table 11 Test Parameters 26 Table 12 Test Matrix by Date 29 Table 13 Events Identified as Possible Data Shift Correlates 31 Table 14 Analysis of Variance for Highway FET Fuel Economy by Tire Type and Collection

Bag Number 33 Table 15 Air Conditioning SC03 Schedule mpg for SRTT Tire by Date 34 Table 16 Change in Fuel Economy Over Total Time of Testing 36 Table 17 Data Excluded from Fuel Economy Analyses 37 Table 18 ANOVA Results for Effect of Tire Rolling Resistance on Fuel Economy 38 Table 19 Percentage Change in Fuel Economy Versus Percentage Change in Tire Rolling

Resistance 38 Table 20 Predicted Change in Fuel Economy for 1 psi Change in Tire Inflation Pressure 44 Table 21 ANOVA Results for Effect of Tire Inflation Pressure Reduction on Fuel Economy 50 Table 22 Correlation of Rolling Resistance to Tangent δ at 60degC 52 Table 23 Correlation of Properties to Rolling Resistance 53 Table 24 Dry Traction Results Traction Number and Ratio to E501 Reference Tire 54 Table 25 Pearson Product Moment Correlation of Dry Traction to Rolling Resistance 54 Table 26 Wet Traction Results Traction Number and Ratio to E501 Reference Tire 57 Table 27 Pearson Product Moment Correlation of Wet Traction to Rolling Resistance 57 Table 28 Pearson R Product Moment Correlation of Wet Traction to 62 Table 29 Analysis of Tire Wear Data 63 Table 30 Wear Rates and Projected Mileage to 232nds Tread Depth 64 Table 31 Indoor Treadwear Tire Wear Data 66 Table 32 Projected Mileage to 232nds Inch of Tread Depth 66 Table 33 Projected Lifetime Versus Rolling Resistance ndash Mild Wear at Tread Center 69 Table 34 Projected Lifetime Versus Rolling Resistance ndash Severe Wear at Tread Center 70 Table 35 Projected Lifetime Versus Rolling Resistance ndash Mild Wear at Shoulder 71 Table 36 Projected Lifetime Versus Rolling Resistance ndash Severe Wear at Shoulder 72 Table 37 Analysis of Rolling Resistance Change 76

LIST OF EQUATIONS Equation 1 Rolling Resistance Calculation Force Method (ISO 28580) 9 Equation 2 Rolling Resistance Calculation Torque Method (ISO 28580) 10 Equation 3 Input Cycle 27 Equation 4 SAE J1269 Linear Regression Equation for Passenger Car Tires 87 Equation 5 ISO 28580 Rolling Resistance Coefficient 89 Equation 6 TampRA Load Formula for ldquoPrdquo Type Tires (SI Units) 100

DEFINITIONS

SAE ndash The Society of Automotive Engineers International is an international standards organizashytion providing voluntary standards to advance the state of technical and engineering sciences SAE International 400 Commonwealth Drive Warrendale PA 15096-0001 Tel 877-606-7323 wwwsaeorg

ISO ndash The International Organization for Standardization is a worldwide federation of national standards bodies that prepares standards through technical committees comprised of international organizations governmental and non-governmental in liaison with ISO ISO Central Secretariat 1 ch de la Voie-Creuse Case postale 56 CH-1211 Geneva 20 Switzerland Telephone +41 22 749 01 11 Fax +41 22 733 34 30 wwwisoorg

SAE J1269 (Rev September 2006) ndash ldquoSAE multi-point standard Rolling Resistance Measureshyment Procedure for Passenger Car Light Truck and Highway Truck and Bus Tires This proceshydure is intended to provide a standard method for gathering data on a uniform basis to be used for various purposes (for example tire comparisons determination of load or pressure effects correlation with test results from fuel consumption tests etc)rdquo A single-point test condition (SRC or standard reference condition) is included The rolling resistance at this condition may be calculated from regression of the multi-point measurements or measured directly at the SRC

SAE J2452 (Issued June 1999) ndash ldquoStepwise Coastdown Methodology for Measuring Tire Rollshying Resistance This SAE Recommended Practice establishes a laboratory method for determinashytion of tire rolling resistance of Passenger Car and Light Truck tires The method provides a stanshydard for collection and analysis of rolling resistance data with respect to vertical load inflation pressure and velocity The primary intent is for estimation of the tire rolling resistance contribushytion to vehicle force applicable to SAE Vehicle Coastdown recommended practices J2263 and J2264rdquo

ISO 181642005(E) ndash ldquoPassenger car truck bus and motorcycle tires -- Methods of measuring rolling resistance This International Standard specifies methods for measuring rolling resistance under controlled laboratory conditions for new pneumatic tyres designed primarily for use on passenger cars trucks buses and motorcyclesrdquo

ISO 28580 Draft International Standard (DIS) ndash ldquoTyre Rolling Resistance measurement method ndash single-point test and measurement result correlation ndash designed to facilitate internashytional cooperation and possibly regulation building Passenger Car Truck and Bus Tyres This recommendation specifies methods for measuring rolling resistance under controlled laboratory conditions for new pneumatic tyres designed primarily for use on passenger cars trucks and buses Tyres intended for temporary use only are not included in this specification This includes a method for correlating measurement results to allow inter-laboratory comparisons Measureshyment of tyres using this method enables comparisons to be made between the rolling resistance of new test tyres when they are free-rolling straight ahead in a position perpendicular to the drum outer surface and in steady-state conditionsrdquo

Rolling Resistance (Fr) (ISODIS 28580) ndash ldquoLoss of energy (or energy consumed) per unit of distance travelled NOTE 1 The SI unit conventionally used for the rolling resistance is the newshyton metre per metre (N mm) This is equivalent to a drag force in newtons (N)rdquo (Also referred to as ldquoRRFrdquo)

Rolling Resistance Coefficient (Cr) (ISODIS 28580) ndash ldquoRatio of the rolling resistance in newshytons to the load on the tyre in knewtons This quantity is dimensionlessrdquo (Often multiplied by 1000 kgmetric tonne (MT) for reporting Also referred to as RRC)

Mean Equivalent Rolling Force (MERF) (SAE 2452) ndash ldquoThe average rolling resistance of a tire at a given loadinflation condition over a driving cycle with a specified speed-time profile This implicitly weights the rolling resistance for each speed using the length of time spent at that speed during the cyclerdquo For the purpose of this document MERF is a combined weighting of MERFs calculated using the standard EPA urban and highway driving cycles Specifically this weighting is 55 percent for the EPA Urban (FTP) Cycle and 45 percent for the EPA Highway Fuel Economy Cycle

Standard Mean Equivalent Rolling Force (SMERF) (SAE 2452) ndash ldquoFor any tire is the MERF for that tire under standard loadinflation conditions defined in 310rdquo For this document the fishynal SMERF is also calculated by weighting the SMERF obtained for the EPA urban and highway cycles as discussed previously for MERF calculation

Tire Spindle Force Ft (ISODIS 28580) ndash ldquoForce measured at the tire spindle in newtonsrdquo

Tire Input Torque Tp (ISODIS 28580) ndash ldquoTorque measured in the input shaft at the drum axis measured in newton-metersrdquo

Capped Inflation (ISODIS 28580) ndash ldquoInflating the tire and fixing the amount of inflation gas in the tire This allows the inflation pressure to build up as the tire is warmed up while runningrdquo

Parasitic Loss (ISODIS 28580) ndash ldquoLoss of energy (or energy consumed) per unit of distance excluding internal tire losses and attributable to aerodynamic loss of the different rotating eleshyments of the test equipment bearing friction and other sources of systematic loss which may be inherent in the measurementrdquo

Skim Test Reading (ISODIS 28580) ndash ldquoType of parasitic loss measurement in which the tire is kept rolling without slippage while reducing the tire load to a level at which energy loss within the tire itself is virtually zerordquo

EXECUTIVE SUMMARY

The first phase of development of the tire fuel efficiency rating system consisted of the evaluashytion of five laboratory rolling resistance test methods using 25 light-vehicle tire models in dushyplicate at two independent laboratories Results of this evaluation are documented in the Phase 1 report on the project The agencyrsquos evaluation showed that all of the rolling resistance test methshyods had very low variability and all methods could be cross-correlated to provide the same inshyformation about individual tire types The rank order grouping of tire types was statistically the same for each of the rolling resistance test methods evaluated However the relative rankings of the tires within the population of the 25 models tested shifted considerably when tires were ranked by either rolling resistance force or rolling resistance coefficient

It was concluded from Phase 1 that while multi-point rolling resistance test methods are necesshysary to characterize the response of a tirersquos rolling resistance over a range of loads pressures andor speeds either of the two shorter and less expensive single-point test methods were suffishycient for the purpose of simply assessing and rating individual tires in a common system Of the two single-point methods the ISO 28580 Draft International Standard (DIS) has the advantage of using defined lab alignment tires to allow comparison of data between labs on a standardized bashysis The use of any of the other single or multi-point test standard would require extensive develshyopment of a method to allow direct comparison of results generated in different laboratories or even on different machines in the same laboratory In addition the Commission of the European Communities (EU) has selected ISO 28580 international standard as the basis of its rolling resisshytance rating system Use of ISO 28580 would allow international harmonization of US and European test practices

This report summarizes the results of testing done to examine possible correlations between tire rolling resistance levels and operating parameters such as vehicle fuel economy wet and dry traction and outdoor and indoor treadwear With the exception of the OE tires on the fuel econshyomy vehicle all tires used in Phase 2 were previously tested in one to two indoor rolling resisshytance tests in Phase 1 Fifteen different tire models were installed on the same new passenger car to evaluate the effects of tire rolling resistance levels on vehicle fuel economy using a test that approximately followed the EPArsquos new 5-cyle dynamometer test A 10-percent decrease in tire rolling resistance resulted in approximately 11-percent increase in fuel economy for the vehicle This result was within the range predicted by technical literature Reducing the inflation pressure by 25 percent resulted in a small but statistically significant decrease of approximately 03 to 05 miles per gallon for four of the five fuel economy cycles excluding the high-speed high-acceleration US06 cycle This value was smaller than many values predicted by technical literashyture and possible explanations are being explored

Sixteen tire models were subjected to dry and wet skid-trailer testing on asphalt and concrete skid pads Both the peak (maximum) and slide (fully locked-tire) coefficients of friction were measured and indexed against the control tire For the tires studied there appeared to be no sigshynificant relationship between dry peak or slide numbers and rolling resistance However these tire models exhibited a strong and significant relationship between better rolling resistance and poorer wet slide numbers The peak wet slide number displayed the same tendency but the relashytionship was much weaker This may be significant to consumers without anti-lock braking sysshy

tems (ABS) on their vehicles since the wet slide value relates most closely to locked-wheel emergency stops For newer vehicles with ABS or electronic stability control systems which opshyerate in the earlier and higher peak friction range the tradeoff is less significant The agencyrsquos current Uniform Tire Quality Grading Standards (UTQGS) (575104) rate wet slide traction but not wet peak traction For the subset of five tire models subjected to on-vehicle treadwear testing (UTQGS) no clear relationship was exhibited between tread wear rate and rolling resistance levshyels For the subset of six tire models subjected to significant amounts of wear in the indoor treadwear tests there was a trend toward faster wear for tires with lower rolling resistance

The Requirements section of the report contains an analysis of the various options in the draft ISO 28580 rolling resistance test and their likelihood of inducing variability in the test results The lab alignment procedure in ISO 28580 which for passenger tires uses two dissimilar tires to calibrate a test lab to a master lab states that it will compensate for differences induced from tests conducted using different options under the test standard These options include the use of one of four measurement methods (force torque power or deceleration) textured or smooth drum surface correction of data to a 25C reference temperature and correction of data from tests conducted on a test drum of less than 20-m in diameter to a 20-m test drum The variabilshyity in test results induced by allowing the various test options as well as the effectiveness of the temperature and test drum correction equations is not currently known to the agency Some recshyommendations are included

Concluding the report is a special discussion regarding the use of rolling resistance (Fr) or rolling resistance coefficient (Cr) as the basis for data reporting and ratings The ISO 28580 standard calculates a rolling resistance (Fr energy loss per unit distance) from one of four different measshyurement methods Since rolling resistance varies with the load on the tire and tires of different load indexes are tested at different loads the rolling resistance coefficient is used to allow a relashytive comparison of the energy consumption of tires of all sizes and load ranges However the normalization of Fr to generate Cr is not consistent across the range of tire sizes and load ranges in what is expected to be about 20000 different tires in a common system If the Cr coefficient is used as a basis the data will be skewed towards better ratings for larger tires While this would have negligible effects for consumers picking out tires of a given size there are concerns about the confusion of consumers if the overall tire fuel economy system was to rate tires that consume more fuel at a given set of conditions better than tires that consume less fuel at those same condishytions

10 INTRODUCTION

Reducing energy consumption is a national goal for many reasons from economic and national security to improving air quality and reducing greenhouse gas emissions Also rising energy prices are having their effect on consumers and businesses and have contributed to increases in the Consumer Price Index in recent years Hall and Moreland define tire rolling resistance ldquoas the energy consumed per unit distance of travel as a tire rolls under loadrdquo[1] A vehiclersquos fuel econshyomy is affected by tire rolling resistance therefore fuel saving could be achieved by reducing tire rolling resistance Low-rolling-resistance original equipment (OE) tires are used by auto manufactures to help meet the Federal fuel economy standards for new passenger cars and light trucks However consumers often purchase less fuel-efficient tires when replacing their vehishyclesrsquo OE tires as well as when purchasing subsequent sets of replacement tires For example during 2007 there were an estimated 51 million OE passenger and light truck tires sold in the United States as opposed to an estimated 237 million replacement passenger and light truck tires[2] Therefore the rolling resistance of replacement tires could have a significant impact on the fuel economy of the US light-vehicle fleet

In the Consolidated Appropriations Act of 2004 Congress provided funding through the NHTSA to the National Academy of Sciences (NAS)1 to develop and perform a national tire fuel effishyciency study and literature review[3] The NAS was to consider the relationship that low rolling resistance tires designed for use on passenger cars and light trucks have with vehicle fuel conshysumption and tire wear life The study was to address the potential of securing technically feasishyble and cost-effective fuel savings from low rolling resistance replacement tires that do not adshyversely affect tire safety including the impacts on performance and durability or adversely imshypact tire tread life and scrap tire disposal and that does fully consider the average American lsquolsquodrive cyclersquo The study was to further address the cost to the consumer including the additional cost of replacement tires and any potential fuel savings The resulting NAS Transportation Reshysearch Board report of April 2006 concluded that reduction of average rolling resistance of reshyplacement tires by 10 percent was technically and economically feasible and that such a reducshytion would increase the fuel economy of passenger vehicles by 1 to 2 percent saving about 1 to 2 billion gallons of fuel per year nationwide However as is common in such studies the NAS committee did not have a mechanism to generate its own test data2 and conclusions were based upon available literature and data[4] The tire industry eventually supplied rolling resistance data for 214 passenger and light truck tire models to the NAS committee (177 Michelinshy

1 Ultimately the Committee for the National Tire Efficiency Study of the Transportation Research Board a division of the National Research Council that is jointly administered by the National Academy of Sciences the National Academy of Engineering and the Institute of Medicine 2 NAS cautioned that much of the available technical literature on tire rolling resistance dates back to the mid-1970s to mid-1980s Data on ldquotodayrsquosrdquo passenger tires was difficult to obtain

manufactured 24 Bridgestone-manufactured and 13 Goodyear-manufactured passenger and light truck tires)3

The Transportation Research Board report suggests that safety consequences of a 10-percent imshyprovement in tire rolling resistance ldquowere probably undetectablerdquo However the committeersquos analysis of grades under UTQGS (FMVSS No 575104) for tires in its study indicated that there was difficulty in achieving the highest wet traction andor treadwear grades while achieving the lowest rolling resistance coefficients This was more noticeable when the sample of tires was constrained to similar designs (similar speed ratings and diameters) A lack of access to the raw rating numbers instead of the final grades provided by the manufacturers prohibited a more deshytailed analysis

Subsequent to the publication of the NAS committee report NHTSA initiated a research proshygram to evaluate five laboratory rolling resistance test methods using 25 currently available light vehicle tire models in duplicate at two independent laboratories Results of this evaluation are documented in the Phase 1 report of the project The agencyrsquos evaluation showed that all of the rolling resistance test methods had very low variability and all methods could be cross-correlated to provide the same information about individual tire types Differences of as much as 30 percent in measured rolling resistance force were observed between different models of tires of the same size It was concluded that while multi-point rolling resistance test methods are necessary to characterize the response of a tirersquos rolling resistance over a range of loads pressures andor speeds either of the two shorter and less expensive single-point test methods were sufficient for the purpose of simply assessing and rating individual tires in a common system Of the two sinshygle-point methods evaluated the ISO 28580 Draft International Standard (DIS) has the advanshytage of using defined lab alignment tires to allow comparison of data between labs on a standardshyized basis The use of any of the other single or multi-point test standard would require extensive development of a method to allow direct comparison of results generated in different laboratoshyries or even on different machines in the same laboratory Also the Commission of the Euroshypean Communities (EU) has selected ISO 28580 international standard as the basis of its rolling resistance rating system Use of ISO 28580 would allow international harmonization of US and European test practices

In December 2007 Congress enacted the Energy Independence and Security Act of 2007 that mandated that NHTSA establish a national tire fuel efficiency rating system for motor vehicle replacement tires within 24 months While the existing research program was sufficient to meet the requirements for the testing and rating requirements NHTSA initiated a second phase of reshysearch to address the safety and consumer information requirements Portions of Phase 2 of the project retested up to 15 models of Phase 1 tires as well the original equipment tires on the fuel economy test vehicle to examine possible correlations between tire rolling resistance levels and operating parameters such as vehicle fuel economy wet and dry traction and outdoor and indoor

3 NAS ldquoBefore the committeersquos final meeting several tire manufacturers acting through the Rubber Manufacturers Association made available measurements of the rolling resistance of a sample of more than 150 new replacement passenger tires as well as some original equipment (OE) tires Although the sample was not scientifically derived the data proved helpful to the committee as it sought to answer the various questions in the study charge The timing of the datarsquos availability late in the study process limited the statistical analyses that could be undertaken by the committeerdquo Reference [4] Page ix

treadwear This was accomplished through on-vehicle EPA dynamometer fuel economy tests wet and dry skid-trailer traction tests on-vehicle treadwear tests and experimental indoor tread-wear tests

11 The Concept of Rolling Resistance

In the latest version of the book The Pneumatic Tire which was commissioned and published by NHTSA LaClair describes the concept of rolling resistance in simple terms[5]

ldquoWhen a tire rolls on the road mechanical energy is converted to heat as a result of the phenomenon referred to as rolling resistance Effectively the tire consumes a portion of the power transmitted to the wheels thus leaving less energy available for moving the vehicle forward Rolling resistance therefore plays an important part in increasing vehicle fuel consumption hellip Rolling resistance includes mechanical energy losses due to aeroshydynamic drag associated with rolling friction between the tire and road and between the tire and rim and energy losses taking place within the structure of the tirerdquo

LaClair also points out that the term rolling resistance is often mistaken as a measure of the force opposing tire rotation when instead is actually a measure of rolling energy loss[6]

ldquoAlthough several authors recognized the importance of energy consumption the concept of rolling resistance as a retarding force has persisted for many years Schuring provided the following definition of rolling resistance as a loss in mechanical energy ldquoRolling [reshysistance] is the mechanical energy converted into heat by a tire moving for a unit distance on the roadwayrdquo He proposed the term rolling loss instead of rolling resistance so that the long-standing idea of a force would be avoided hellip Schuring pointed out that although rolling resistance -- defined as energy per unit distance -- has the same units as force (Jm = N) it is a scalar quantity with no direction associated with itrdquo

Defining rolling resistance as an energy loss is advantageous when considering its effects on the fuel efficiency of a vehicle The US Department of Energy estimates that approximately 42 percent of the total energy available in the fuel you put in your tank is lost to rolling resistance during the operation of the vehicle (Figure 1)[7] However Duleep and NAS point out that the peak first law (thermodynamic) efficiency of a modern spark-ignited gasoline engine is in the 34shy36 percent range (40-42 for diesels) and therefore tire rolling resistance consumes about a third of the usable energy actually transmitted to the wheels (ie 13 of the available tractive energy) Therefore considering rolling resistance in terms of the energy in the fuel tank is not a useful measure[8][9] For instance in Figure 1 only 126 percent of the energy in the fuel is fishynally transmitted to the wheels The 42 percent of original fuel energy used by rolling resistance is actually 33 percent (42126) of the total usable energy available to the wheels

Only about 15 percent of the energy from the fuel you put in your tank gets used to move your car down the road or run useful accessories such as air conditioning The rest of the energy is lost to engine and driveline inefficiencies and idling Therefore the potential to improve fuel efficiency with advanced techshynologies is enormous

Rolling Resistance ndash 42 percent For passenger cars a 5 to 7 percent reduction in rolling resistance increases fuel efficiency by 1 percent However these improvements must be balanced against traction durability and noise

Figure from Department of Energy 2009

Figure 1 Where Does the Energy Go

Additionally the contribution of tire rolling resistance to fuel economy varies with the speed of the vehicle At lower speeds tire rolling resistance represents a larger percentage of the fuel conshysumption (Figure 2) than at higher speeds[10]

Figure 2 Contribution of Tire Rolling Resistance to Vehicle Fuel Economy Versus Speed (Reprinted with permission from the Automotive Chassis Engineering Principles

2nd Edition Reed Educational and Professional Publishing Ltd 2001)

In any discussion of rolling resistance it is important to consider that the rolling resistance level of a tire evolves during use It is reported in literature that a tirersquos rolling resistance level and therefore its effects on vehicle fuel economy can decrease by more than 20 percent from a new tread to completely worn[11][12] Therefore calculations of the benefits of lower tire rolling resistance derived from measurements of new tires will likely understate the benefits to a vehicle in terms of absolute fuel economy over the lifetime of the set of tires However since both new-vehicle fuel economy and new-tire rolling resistance change with time and are dependent on usshyage conditions age and maintenance levels attempts to calculate lifetime benefit can vary widely

While the hysteretic losses of the tire (primarily the tread) consume a large amount of the availshyable tractive energy the tires also provide the traction necessary to start stop and steer the vehishycles Substances soft enough to provide traction on wet dry snow dirt gravel etc surfaces will also wear Therefore the topics of rolling resistance traction and treadwear are linked in what the tire industry refers to as the ldquomagic trianglerdquo (Figure 3) The triangle is a useful graphic since it conveys the point that a shift to improve properties in one corner of the triangle can diminish properties in both of the other corners if more advanced and often more expensive tire comshypounding and construction technologies are not employed

Rolling Resistance

Traction

Treadwear

Figure 3 Magic Triangle Traction Treadwear and Rolling Resistance

From a safety standpoint the obvious concern from the magic triangle is a loss of tire traction to achieve lower rolling resistance (better vehicle fuel economy) Since 85 percent of all crashes in 2005 occurred during normal dry weather conditions and 10 percent in the rain (Table 1) the effects of lower rolling resistance on wet and dry traction are of primary importance[13] Longishytudinal wet and dry tire traction are easily measured with skid-trailer testing Conversely while crashes occur on snow sleet and ice about 4 percent of the time measuring tire traction on the varying permutations of these surfaces is not easily done

Table 1 2005 Motor Vehicle Crash Data From FARS and GES Crashes by Weather Condition

Weather Condition All Crashes Percent Normal (dry) 5239000 851 Rain 584000 95 SnowSleet 264000 43 Other 72000 12 Total 6159000 100

20 METHODOLOGY

21 Test Tires

The majority of the tire models selected for Phase 1 were size P22560R16 or 22560R16 which in 2007 was the most popular size of replacement tire in the United States Phase 1 of the project evaluated the rolling resistance of 25 passenger and light-truck tire models However time and budget constraints as well as equipment limitations limited Phase 2 to retests of 5 to 16 of the Phase 1 models in different portions of the project (Table 2) The original equipment tires on the fuel economy test vehicle added a 17th tire model to the Phase 2 test matrix The Phase 2 tire models ranged from 14- to 17-inch rim codes Q to W speed ratings 9 to 15 lbf (7 to 11 Cr) in rolling resistance per ISO 28580 19 to 36 lbs in weight 300 to 700 in treadwear rating and A to AA in UTQGS traction (wet) rating

The Phase 1 passenger tires all purchased as new were not subjected to optional break-ins listed in the various rolling resistance tests prior to the warm-up and measurement phases of the tests Therefore Phase 1 tires experienced approximately 50 to 75 miles of straight-line mileage on the laboratory rolling resistance machine prior to Phase 2 testing This produced no detectable treadwear but did serve to break-in the tires It has been reported by LaClair that tire rolling reshysistance will decrease about 2-5 percent during a break-in period of 60 minutes at 80 kmh (50 total miles)[14] Therefore it is anticipated that the rolling resistance of the tires retested in Phase 2 for on-vehicle fuel economy traction and treadwear is approximately 2-5 percent lower than a brand new tire subjected to these tests However it should also be noted that most of these tests are normally completed with tires that are broken-in prior to testing (vehicle fuel economy - 2000 miles outdoor traction - 200 miles outdoor treadwear - 800 miles)

211 ASTM F2493 Radial Standard Reference Test Tire

Tire model M14 is an ASTM F2493 SRTT tire The ASTM F2493 - Standard Specification for P22560R16 97S Radial Standard Reference Test Tire (SRTT) provides specifications for a tire ldquofor use as a reference tire for braking traction snow traction and wear performance evaluations but may also be used for other evaluations such as pavement roughness noise or other tests that require a reference tirerdquo The standard contains detailed specifications for the design allowable dimensions and storage of the tires The F2493 SRTT is a variant of a modern 16-inch Uniroyal TigerPaw radial passenger vehicle tire and comes marked with a full USDOT Tire Identification Number and UTQGS grades The SRTTs were used extensively throughout the laboratory test surface and fuel economy phases of the test program to monitor the stability of the testing The SRTTs had the added advantage of being near the center of the range of passenger tire rolling resistances in the program (Table 2)

Table 2 Phase 2 Tire Models T

G12 Goodyear P22560R16 97 S Integrity 460 A B Passenger All Seashyson TPC 1298MS

947 736 220

G8 Goodyear 22560R16 98 S Integrity 460 A B Passenger All Seashyson

983 744 229

G11 Goodyear P22560R17 98 S Integrity 460 A B Passenger All Seashyson

1002 758 245

B11 Bridgestone P22560R16 97 H Potenza RE92 OWL

340 A A High Performance All Season

1013 787 251

1127 919 192

M14 Uniroyal P22560R16 97 S ASTM 16 SRTT

540 A B ASTM F 2493-06 Reference

1196 930 255

M13 Michelin 22560R16 98 H Pilot MXM4 300 A A Grand Touring All Season

1207 913 247

1209 946 204

B10 Bridgestone 22560R16 98 Q Blizzak REVO1

- Performance Winter 1211 916 269

D10 Cooper 22560R16 98 H Lifeliner Tourshying SLE

420 A A Standard Touring All Season

1356 1026 252

B14 Bridgestone P22560R16 97 V Turanza LS-V 400 AA A Grand Touring All Season

1390 1080 286

U3 Dunlop (Sumitomo)

P22560R17 98 T SP Sport 4000 DSST

360 A B Run Flat 1391 1052 364

B15 Dayton 22560R16 98 S Winterforce - Performance Winter 1399 1058 267

P5 Pep Boys (Cooper)

P22560R16 97 H Touring HR 420 A A Passenger All Seashyson

1402 1089 257

R4 Pirelli 22560R16 98 H P6 Four Seashysons

400 A A Passenger All Seashyson

1498 1133 243

B13 Bridgestone P22560R16 97 T Turanza LS-T 700 A B Standard Touring All Season

1501 1166 294

B12 Bridgestone P22560R16 98 W Potenza RE750 340 AA A Ultra High Performshyance Summer

1522 1151 274

Original equipment tires on the fuel economy test vehicle

Standard reference test tires used as control tires throughout all phases of the study

Snow tires will not be rated in the national tire fuel efficiency consumer information program

22 Tire Rolling Resistance Test Procedures

Tire rolling resistance is measured in a laboratory under controlled conditions The test condishytions vary between the various SAE and ISO test standards but the basic premise is the same in that a tire is mounted on a free-rolling spindle with no camber or slip angle loaded against a large-diameter powered test drum turned by the drum to simulate on-road rolling operation and some measure of rolling loss evaluated Referring back to the book The Pneumatic Tire[5]

ldquoRolling resistance is the effort required to keep a given tire rolling Its magnitude deshypends on the tire used the nature of the surface on which it rolls and the operating condishytions - inflation pressure load and speedrdquo

This description is important because it emphasizes that rolling resistance is not an intrinsic property of the tire rather a function of many operating variables This is why multi-point laboshyratory tests measure a tirersquos rolling resistance over a range of inflation pressures loads and for some tests a range of speeds Conversely single-point point rolling resistance test methods use a single set of these variables to estimate the rolling resistance of the tire under nominal straight-line steady state operating conditions (the vast majority of a tirersquos rolling operation) In the case of a laboratory test rolling resistance (energy loss) is calculated by measuring the amount of adshyditional force torque or power necessary to keep the tire rolling at the test conditions A fourth method which is not widely used is a deceleration method in which the energy source is de-coupled from the system and the rate of loss of angular momentum (energy loss) imparted by the tire is measured

The two domestic test labs used by the agency had machines that used either the force or the torque measurement method A picture of a laboratory rolling resistance test using a force method can be seen in Figure 4 The machine measures a reaction force at the axle of the test tire amp wheel assembly The drum is brought up to speed and the tire is warmed up to an equilibrium temperature The tire is then lightly loaded to measure ldquoparasiticrdquo losses caused by the tire spinshydle friction aerodynamic losses and the test drumdrive system bearings The tire is then loaded to the test load and successive readings are taken until consistent force values are obtained Durshying the test the loaded radius (rL) of the tire is measured during the steady-state conditions In ISO 28580 the Rolling Resistance (Fr) at the tiredrum interface is calculated from the measured force at the spindle (Ft) multiplied by a ratio of the loaded tire radius (rL) to the test wheel radius (R) minus the skim load (Fpl)

Fr = Ft[1+(rLR)]-Fpl

Equation 1 Rolling Resistance Calculation Force Method (ISO 28580)

Ft = Spindle Force

Fr = Calculated Rolling Resisshytance at TireDrum Interface

17 meter Drum

Torque Cell 17 meter roadwheel

80 grit Surface

T = torque

Figure 4 Force Method Rolling Resistance Test Machine

Another test lab used by the agency used a torque method machine The torque method measures the torque required to maintain the rotation of the drum The drum is connected to the motor through a ldquotorque cellrdquo (Figure 5) The drum is brought up to speed and the tire is warmed up to an equilibrium temperature The tire is then lightly loaded to measure the losses caused by the axle holding the tire and aerodynamic losses from the tire spinning The tire is then loaded to the test load and successive readings are taken until consistent torque (Tt) values are obtained

Fr = TtR-Fpl

Equation 2 Rolling Resistance Calculation Torque Method (ISO 28580)

Figure 5 Torque Method Rolling Resistance Test Machine

In one additional calculation the rolling resistance force (Fr) calculated by any of the methods is divided by the nominal test load on the tire to produce the rolling resistance coefficient (Cr) Since the rolling resistance coefficient (Cr) is not linear between tires of different load ranges the rolling resistance (Fr) for each tire was compared to the traction treadwear and fuel econshyomy measures in the Phase 2 analysis

Tires in Phases 1 and 2 were subjected to up to three tests The first and possibly second test may have been the same indoor rolling resistance test or two different tests followed by traction treadwear or fuel economy testing A detailed test matrix is provided in Appendix 2 A descripshytion of the laboratory rolling resistance tests used in Phase 1 follows

221 ISO Draft International Standard 28580 Single-Point Rolling Resistance

Tires from all 17 tire models used in Phase 2 though not necessarily the exact tires were previshyously tested using the draft ISO 28580 test method

222 SAE J1269 amp ISO 18164 Multi-Point Rolling Resistance

Tires from all 17 tire models in Phase 2 though not necessarily the exact tires were previously tested with SAE J1269 and 11 models were previously tested with ISO 18164 (both tests are very similar) Data from this multi-point test allows estimation of tire rolling resistance at the test vehicle load and the two inflation pressures used in the vehicle fuel economy testing

223 SAE J2452 Multi-Point (Speed Coast Down) Rolling Resistance

With the exception of the original equipment (OE) tires tires from 16 tire models in Phase 2 though not necessarily the exact tires were previously tested with SAE J2452 Data from this multi-point test allows estimation of tire rolling resistance at the test vehicle load two inflation pressures and speeds used in the vehicle fuel economy testing

23 Fuel Economy Test Vehicle

A 2008 Chevrolet Impala LS was selected as the test vehicle for fuel economy testing since it came equipped with P22560R16 tires and GM original equipment tires have a Tire Performance Code (TPC) that allows purchase of replacement tires with the same specifications as the OE tires These OE tires (tire type G12) became the 17th group of tires in Phase 2 and had the lowest rolling resistance of any tire tested in the program (Table 2)

24 Test Wheels

Tires were tested on wheels of the corresponding ldquomeasuring rim widthrdquo for their size Wheels of each size used in the test program were purchased new in identical lots to minimize wheel-toshywheel variation A tire participating in multiple tests throughout the test program was mounted

once on a single new wheel and continued to be tested on that same wheel until completion of all tests

25 Test Matrix

The EISA legislation requires a national tire fuel efficiency consumer information program ldquoto educate consumers about the effect of tires on automobile fuel efficiency safety and durabil-ityrdquo[15] Phase 2 of the project was therefore designed to examine the effects of tire rolling resisshytance levels on vehicle fuel economy traction and treadwear Phase 1 tires were retested in one of five Phase 2 test protocols On-vehicle EPA dynamometer fuel economy (Dyno FE) wet and dry skid-trailer traction on-vehicle treadwear an experimental indoor treadwear test or tread rubber analysis by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) (Table 3) Due to time and cost considerations as well as the physical constraints the fuel econshyomy test vehicle and skid-trailer the four tests used a subset of the 17 available Phase 2 tire models selected to cover the range of rolling resistance values in the experiment

Table 3 Test Matrix Code MFG Size Load

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

DMA G12 Goodyear P22560R16 97 S Integrity 947 x x G8 Goodyear 22560R16 98 S Integrity 983 x x x x x G11 Goodyear P22560R17 98 S Integrity 1002 x x x B11 Bridgestone P22560R16 97 H Potenza

RE92 OWL 1013 x x x x x

G9 Goodyear P20575R14 95 S Integrity 1127 x x M14 Uniroyal P22560R16 97 S ASTM 16

SRTT 1196 x x x x x

M13 Michelin 22560R16 98 H Pilot MXM4 1207 x x x x x G10 Goodyear P20575R15 97 S Integrity 1209 x x B10 Bridgestone 22560R16 98 Q Blizzak

REVO1 1211 x x x

D10 Cooper 22560R16 98 H Lifeliner Touring SLE

1356 x x x

B14 Bridgestone P22560R16 97 V Turanza LS-V

1390 x x x

1391 x x x

B15 Dayton 22560R16 98 S Winterforce 1399 x x x P5 Pep Boys

(Cooper) P22560R16 97 H Touring HR 1402 x x x

R4 Pirelli 22560R16 98 H P6 Four Seasons

1498 x x x

B13 Bridgestone P22560R16 97 T Turanza LS-T

1501 x x x x x

B12 Bridgestone P22560R16 98 W Potenza RE750

1522 x x x

Original equipment tires on the fuel economy test vehicle Standard reference test tires used as control tires throughout all phases of the study

26 Tread Compound Properties Testing

The tread rubber of 16 Phase 1 passenger tires was analyzed for compound composition by thermogravimetric analysis (TGA) The mechanical properties of the treads were evaluated by dynamic mechanical analysis (DMA) TGA is a useful tool for characterizing polymer composishytions The weight loss as a function of temperature has been used to determine polymer loading rubber chemical loading carbon black loading and ash levels For polymers with very different thermal stabilities the TGA curves can be used to determine the amount of each polymer preshysent Thermogravimetric analysis was performed using about 10 mg of sample of each tire tread The purge (He) gas flow rate to the TGA was set at 10mlmin during weight loss measurements The heating rate was 10Cmin to improve the resolution of small variations in the decomposishytion curves At 600C the purge gas was switched over to air for carbon black combustion These average values represent the average of three measurements Figure 6 shows a representashy

100 Volatile Components

Polymer 40

20 Carbon Black

Ash (Zinc Oxide Silica hellip0

0 200 400 600 800 1000 Temperataure (degC)

tive weight loss curve with the regions that represent each component identified The results of the TGA analysis are shown in Table 4

Figure 6 Sample TGA Weight Loss Curve

Table 4 Analysis of Tread Composition by TGA Tire Black Type

Polymer (325-550C)

Volatiles phr (25shy325degC)

phr (550shy

850C) Ash phr (Residue)

Total Filler phr

Silica phr

Total Formulation

phr B10 3104 57 18 32 25 51 19 169 B11 3129 568 18 31 27 52 21 170 B12 3154 49 25 54 25 73 19 198 B13 3179 513 22 44 29 67 23 189 B14 3204 52 25 13 54 62 48 186 D10 3313 469 33 77 3 77 0 207 B15 3337 543 19 63 3 63 0 178 U3 3362 524 18 33 40 67 34 185 G8 3412 604 15 38 12 45 6 159 G9 3441 529 23 60 6 60 0 183 G10 3466 583 22 45 4 45 0 165 G11 3491 633 15 33 11 37 5 152 M13 3620 543 19 10 55 59 49 178

Tire Type

Polymer (325-550C)

Black phr Volatiles Total Total

(550-phr (25- Ash phr 325degC) 850C) (Residue)

Filler Silica Formulation phr phr phr

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

Typical examples of temperature sweep data by the tension method and the shear method are shown below in Figure 7 and Figure 8 The viscoelastic (dynamic mechanical) properties of a tire tread have been correlated to the performance of tires[16][17][18][19] Decreased tangent at 60C is used as a predictor of the tread compoundrsquos contribution to tire rolling resistance In-creased tangent at 0C has been shown to correlate to the wet traction performance of the tire Since these properties tend to move in parallel lowering the tangent at 60C while maintaining a high tangent at 0C normally requires utilization of advanced and often more expensive com-pounding technologies The DMA results for high tangent at 0C and 60C are shown in Table 5

-150 -100 -50 0 50 100

Temperatue (C)

Figure 7 Tan as a Function of Temperature From the Tension Test

-100 -50 0 50 100

Temperature (deg C)

Figure 8 Tan as a Function of Temperature From the Shear Test

Table 5 DMA Results for Tangent at 0C and 60C Tire Type

Rolling Resistance

Tension Shear Tan at

0degC Tan at

60degC Ratio 060 Tan at

0degC Tan at

60degC Ratio 060

G8 3412 983 0169 00762 222 0164 00689 238 G11 3491 1002 0174 0086 202 0177 00754 235 B11 3129 1013 0194 00771 252 0174 0067 260 G9 3441 1126 0245 0188 130 018 0152 118 M14 3720 1196 0287 0193 149 0202 0146 138 M13 3620 1206 0254 0147 173 0168 0117 144 G10 3466 1209 0242 0181 134 0184 0151 122 B10 3104 1211 02 0155 129 016 0133 120 D10 3313 1356 026 0192 135 0183 016 114 B14 3204 1390 0313 0145 216 0233 0132 177 U3 3362 1391 0256 0173 148 0202 0147 137 B15 3337 1398 0208 015 139 0158 0123 128 P5 3670 1402 0271 0207 131 0161 0156 103 R4 3695 1498 0296 0201 147 0211 0159 133 B13 3179 1501 0265 0168 158 019 0138 138 B12 3154 1522 0387 0193 201 028 0146 192 ISO 28580 single-point rolling resistance

27 On-Vehicle Fuel Economy Testing

The effects of tire rolling resistance on automobile fuel efficiency was evaluated by installing 15 different tire models on a new 2008 Chevrolet Impala LS and evaluating its fuel economy in the 2008 five-cycle EPA fuel economy test[20] Testing was completed under contract by the Transshyportation Research Center Inc (TRC Inc) emissions laboratory Since tire inflation pressure affects the operational rolling resistance of a tire the vehicle fuel economy measurements were conducted at two different tire inflation pressures Testing was completed at the vehicle placard

pressure of 210 kPa (30 psi) Six models were tested at both the placard inflation pressure of 210 kPa and at 158 kPa (23 psi) which represents the tire pressure monitoring system (TPMS) actishyvation threshold of 25 percent inflation pressure reduction It is important to note for reasons that will be explained that these tests were research and not official EPA fuel economy ratings of the test vehicle The many tire sets and repeats of test for statistical analysisdual inflation pressure resulted in the test vehicle acquiring nearly 6000 miles by the end of testing The EPA estimates that new vehicles will not obtain their optimal fuel economy until the engine has broshyken in at around 3000 to 5000 miles[21] Therefore the fuel economy of the test vehicle was expected to improve slightly during the course of testing a factor that was tracked and accounted for by the repeated testing of the control and OE tires at regular intervals throughout the testing

271 EPA 40 CFR Part 86 Dynamometer Fuel Economy Testing

Per EPA 40 CFR Part 86 the new 2008 Chevrolet Impala LS test vehicle was broken in for 2000 miles on a test track To keep the original equipment tires in the same low mileage state as the Phase 1 tires the vehicle was broken-in on a spare set of replacement tires of the original equipment size For this reason even the fuel economy tests of the Impala with the original equipment tires were not official EPA test numbers The original equipment tires were reshyinstalled on the vehicle at placard inflation pressure and the road load coastdown procedure was completed The coastdown procedure generates vehicle-specific coefficients for dynamometer settings and fuel economy calculations

The fuel economy dynamometer is housed in an environmental chamber to control the temperashyture for ambient (68 to 86 degrees F) heated (95 degrees F) or cold (20 degrees F) temperatures The vehicle dynamometer is a 122-meter (48-inch) diameter smooth surface drum located in the floor of the chamber The vehicle is placed atop the dynamometer rolls and restrained to prevent movement (Figure 9a) A fan meeting standard specifications is located in front of the vehicle to provide cooling (Figure 9b) A computer is mounted inside the vehicle to provide the driver with a prescribed speed pattern that must be followed for each test cycle (Figure 9c) The exhaust gas is routed from the vehicle exhaust tailpipe via hoses to a collection system connected to gas anashylyzers (Figure 9d)

Figure 9a Tire on 122 Meter Dynamometer Figure 9b Chamber and Fan

Figure 9c Drive Cycle Computer Figure 9d Exhaust Coupling Figure 9 Vehicle Fuel Economy Dynamometer Testing

Details of the 2008 EPA fuel economy test can be found in Table 6 which is from the EPArsquos wwwfueleconomygov Website[22]

Table 6 2008 EPA Fuel Economy 5-Driving Schedule Test (Source EPA 2009) Driving Schedule Attributes

Test Schedule

City (FTP) Highway (HwFET)

High Speed (US06)

AC (SC03) Cold Temp (Cold CO)

Trip Type Low speeds in stop-and-go urban traffic

Free-flow traffic at highway speeds

Higher speeds harder acceleration amp braking

AC use under hot ambient conditions

City test w colder outside temperashyture

Top Speed 56 mph 60 mph 80 mph 548 mph 56 mph Average Speed

212 mph 483 mph 484 mph 212 mph 212 mph

Max Accelshyeration

33 mphsec 32 mphsec 846 mphsec 51 mphsec 33 mphsec

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Time 312 min 1275 min 99 min 99 min 312 min Stops 23 None 4 5 23 Idling time 18 of time None 7 of time 19 of time 18 of time Engine Startup

Cold Warm Warm Warm Cold

Lab temshyperature

68-86ordmF 95ordmF 20ordmF

Vehicle air conditionshying

Off Off Off On Off

A vehicles engine doesnt reach maximum fuel efficiency until it is warm

Whole vehicle preconditioning must be done between the ambient and cold test cycles Thereshyfore instead of running all five fuel economy cycles sequentially in their traditional order testing with the 15 sets of tires was split into blocks that facilitated a much more rapid test throughput In addition to gather more data for statistical purposes two extra HwFET cycles were run seshyquentially after the first HwFET cycle The testing was conducted at the placard tire inflation pressure of 210 kPa (30 psi) and repeated at the TPMS warning activation pressure of 158 kPa (223 psi) for selected tires

Vehicle Preconditioning

Vehicle preconditioning begins with draining the existing fuel from the vehiclersquos fuel tank and replacing it with a 40 percent fuel tank capacity fill of the specified fuel The vehicle is then driven through one Urban Dynamometer Driving Schedule (UDDS) This procedure is followed by a soak period of at least 12 hours but not exceeding 36 hours All preconditioning procedures are performed at the conditions of the test schedule

FTP Schedule Testing

Following the vehiclersquos soak period the vehicle is pushed not driven onto a chassis dynamomeshyter for a cold start exhaust emissions test (rsquo75 FTP) The Federal test procedure (FTP) simulates normal city driving and collects dilute exhaust emissions into bags for analysis in three phases the cold transient (CT) the cold stable (CS) and the hot transient (HT) The UDDS is followed during the CT and CS and following a ten-minute soak on the dynamometer the first phase or

bag of the UDDS is repeated for the HT The results of these phases are combined to provide grams per mile (gmi) for total hydrocarbons (THC) non-methane hydrocarbons (NMHC) carshybon monoxide (CO) carbon dioxide (CO2) and oxides of nitrogen (NOx) Fuel economy in miles per gallon is determined via the carbon balance method

HwFET Schedule Testing

Following each FTP test the vehicle is kept on the chassis dynamometer and the Highway FET (HwFET) driving cycle was run twice The first running of the HwFET served only to stabilize vehicle temperatures and emissions therefore fuel economy was not measured during this cycle The cycle is repeated and all emissions measurements are taken as described for FTP testing with the exception that a single bag is used to collect the dilute exhaust sample (single phase) Fuel economy in miles per gallon is again determined via the carbon balance method The Phase 2 testing protocol added two additional repeats for the HwFET cycle that were run and measured sequentially

US06 Schedule Testing

This test type is the aggressive-driving portion of the supplemental FTP (SFTP) consisting of higher speeds and acceleration rates

SC03 (AC2 Alternate) Schedule Testing

This test type has been introduced to represent the engine load and emissions associated with the use of air conditioning units in vehicles Since the TRC Inc emissions lab lacks the solar-loading equipment necessary to run a full SC03 test the AC2 alternative was used This alternashytive was only valid for 2000-2001 model year vehicles unless approved by the EPA therefore the result for each individual cycle is reported in this report but not composite 5-cycle numbers for the vehicle[23] The AC2 alternative mimics the SC03 except that the thermal load is simulated by placing the vehiclersquos air conditioning temperature control to full hot air conditioning on and the driverrsquos side window left down In addition the test cell is kept at 76 F and 50 grains of washyter per pound of dry air versus the SC03 requirement of 95 F and 100 grains of water per pound of dry air All other procedures follow the SC03

Cold CO Schedule Testing

This test follows the same driving cycle as the FTP but the test is performed at 20 F and the vehicle is filled with Cold CO specific fuel The vehicle is operated through one UDDS preparation cycle at 20deg F Then the vehicle is parked in a soak chamber maintained at 20 F for a minimum of 12 and a maximum of 36 hours prior to beginning each test Following the 20 F soak the vehicle is pushed into the dynamometer chamber (which is at 20 F) and then operated through the normal FTP test

The program was completed in blocks of tests with the M14 control tires and G12 OE tire run multiple times to track possible vehicle tire and test equipment drift The completed test cycles are summarized in Table 7

Table 7 Fuel Economy Test Schedules Pressure City (FTP) Highway (HwFET) High Speed (US06) AC (SC03) Cold

Temp (Cold CO) 210 kPa 19 57 19 19 19 158 kPa 6 16 6 6 6

Two extra cycles completed after first run to gauge statistical variability

28 Skid-Trailer Tire Traction Testing

FMVSS No 575104 Uniform tire quality grading standards requires manufacturers to provide a (wet slide) traction grade for all tires subject to standard and manufactured after April 1 1980 A formal description follows[24]

ldquoTo assist consumers purchasing new vehicles or replacement tires NHTSA has rated more than 2400 lines of tires including most used on passenger cars minivans SUVs and light pickup trucks Traction grades are an indication of a tires ability to stop on wet pavement A higher graded tire should allow a car to stop on wet roads in a shorter disshytance than a tire with a lower grade Traction is graded from highest to lowest as AA A B and C Of current tires 3 percent are rated ldquoAArdquo 75 percent are rated ldquoArdquo 22 percent are rated ldquoBrdquo only 1 line of tires rated ldquoCrdquordquo

The UTQGS skid-trailer traction testing was performed at the NHTSA test facility on Goodfelshylow Air Force Base in San Angelo Texas The traction grading tests are now performed on a purpose-built oval at the base rather than the original test surface diagram shown in 575104 The test pavements are asphalt and concrete skid pads constructed in accordance with industry specishyfications for skid surfaces ASTM E 5014 reference (control) tires are used to monitor the tracshytion coefficient of the two surfaces (which varies based on environmental conditions surface wear etc) During a normal wet traction test a vehicle tows a skid-trailer (Figure 10) at 40 mph across the test surfaces Water is dispersed ahead of the tire from a water nozzle just before the brake is applied Instrumentation measures the horizontal force as the brake is applied to one wheel of the trailer until lock-up and then held for a few seconds and released The tests are reshypeated for a total of 10 measurements on each surface The candidate (test) tires are conditioned by running for 200 miles on a pavement surface The candidate tires are then fitted to the trailer loaded to a specified load and pressure then subjected to the same testing completed on the conshytrol tires The average sliding coefficient of friction for the candidate tire on each surface is corshyrected using the coefficients of the control tire to yield an adjusted traction coefficient for the candidate tire on each test surface

4 ASTM E 501-94 Standard Specification for Standard Rib tire for Pavement Skid Resistance Tests Available from American Society for Testing and Materials httpastmorg

Figure 10 NHTSA San Angelo Skid-Trailer

Phase 2 traction tests were conducted with tires of 16 models previous tested in Phase 1 Two tires had the highest traction grade ldquoAArdquo 14 tires were graded ldquoArdquo (Table 8) Since these tires experienced some break-in during the 50- to 70-mile rolling resistance tests these tires were only conditioned for 70 miles on a pavement surface rather than the normal 200 miles5 Since the tires were not new and had a reduced break-in the results generated are for research purposes and are unofficial The test matrix was also repeated on dry asphalt and concrete test surfaces The numshyber of measurements on the dry surfaces was reduced to preserve the limited test surface area from rubber buildup

Since modern antilock brakes (ABS) and electronic stability control (ESC) operate in the lower slip and higher friction region the peak coefficient recorded during the traction testing was also used for comparisons in Phase 2 in addition to the slide values used for UTQGS wet traction

5 Two additional tires of a Phase 1 tire model were broken -in for the full 200 miles and compared to a set of two that had the 50- to 70-mile roadwheel break-in There was no significant difference in their traction numbers

Table 8 Phase 2 Wet and Dry Skid-Trailer Test Tires T

B14 Bridgestone P22560R16 97 V Turanza LS-V 400 AA A Grand Touring All Season 1390 286

B12 Bridgestone P22560R16 98 W Potenza RE750 340 AA A Ultra High Performance Sumshymer

1522 274

D10 Cooper 22560R16 98 H Lifeliner Touring SLE 420 A A Standard Touring All Season 1356 252

P22560R16 97 H Touring HR 420 A A Passenger All Season 1402 257

R4 Pirelli 22560R16 98 H P6 Four Seasons 400 A A Passenger All Season 1498 243

B11 Bridgestone P22560R16 97 H Potenza RE92 OWL 340 A A High Performance All Season 1013 251

M13 Michelin 22560R16 98 H Pilot MXM4 300 A A Grand Touring All Season 1207 247

B13 Bridgestone P22560R16 97 T Turanza LS-T 700 A B Standard Touring All Season 1501 294

M14 Uniroyal P22560R16 97 S ASTM 16 SRTT 540 A B ASTM F 2493-06 Reference 1196 255

G8 Goodyear 22560R16 98 S Integrity 460 A B Passenger All Season 983 229

G11 Goodyear P22560R17 98 S Integrity 460 A B Passenger All Season 1002 245

P22560R17 98 T SP Sport 4000 DSST 360 A B Run Flat 1391 364

B10 Bridgestone 22560R16 98 Q Blizzak REVO1 - Performance Winter 1211 269

B15 Dayton 22560R16 98 S Winterforce - Performance Winter 1399 267

29 On-Vehicle Tire Treadwear Testing

FMVSS No 575104 Uniform tire quality grading standards requires manufacturers to provide a treadwear grade for all tires subject to standard and manufactured after April 1 1980 A formal description follows[25]

ldquoTreadwear grades are an indication of a tires relative wear rate The higher the tread-wear number is the longer it should take for the tread to wear down A control tire is asshysigned a grade of 100 Other tires are compared to the control tire For example a tire grade of 200 should wear twice as long as the control tire Of current tires 15 percent are rated below 200 25 percent are rated 201 - 300 32 percent are rated 301 - 400 20 pershycent are rated 401 - 500 6 percent are rated 501 - 600 2 percent are rated above 600rdquo

Additional tires from five of the six models used in UTQG traction testing were tested in the UTQGS treadwear test The five tires with treadwear grades ranging from 300 to 700 were mounted and balanced on 16 x 70 rims The groove depths of the tires were then measured All tires were measured with groove one being the outside groove on the serial side The tires were

then installed on five Mercury Marquis vehicles for testing on the UTQG test route near San Anshygelo Texas (Table 9) The vehicles were loaded to 1182 pounds per wheel within +-1 percent The vehicles were aligned to center of manufacturers specifications for caster and camber and toe

Table 9 On-Vehicle Treadwear Testing

The nine-day test conducted consisted of 400-mile day shifts and 400-mile night shifts for a total of 7200 miles including break-in A Shadow Tracker tracking device was placed in the lead veshyhicle at the beginning of each day shift to record speed miles traveled and stops made The route is described in Figure 11 The tires were rotated on the vehicle every 400 miles and measshyured every 800 miles The vehicles were aligned every 800 miles The vehicles were rotated through the convoy at the end of every 800 miles after break-in The tires from all the vehicles were rotated from vehicle to vehicle every 1600 miles after break-in During the course of the test the highest temperature was 93 degrees Fahrenheit and the lowest temperature was 47 deshygrees Fahrenheit The average high for the nine days was 826 degrees Fahrenheit and the avershyage low was 638 degrees Fahrenheit There were 581 wet miles during the nine days of testing Testing was put on hold for three days due to road closures on the South Loop The tires were then measured at the end of the convoy testing to determine the loss of tread depth More detail of this test may be found in FMVSS No 575104

Figure 11 UTQGS Treadwear Course

210 Indoor Tire Treadwear Testing

The FMVSS No 575104 requires all passenger tires (with some exceptions) manufactured after April 1 1980 to be graded for tread life However advances in radial tire tread compounding since 1980 have resulting in longer life treads that exhibit only a marginal amount of wear after running the 7200-mile UTQGS treadwear course To evaluate the effects of bulk treadwear on tire rolling resistance additional tires of the five Phase 1 tire models subjected to on-vehicle treadwear as well as original equipment tires from the Impala fuel economy vehicle were subshyjected to a more aggressive indoor treadwear test developed by Smithers Scientific Services Inc in Ravenna Ohio (Table 10)

Table 10 Indoor Treadwear Testing T

G12 Goodyear P22560R16 97 S Integrity 460 A B Passenger All Season TPC 1298MS

947 220

The testing was completed on an MTS 860 Durability Machine (Figure 12a) 3048-meter (120shyinch) diameter drum covered with 3M 180micro (microfinishing) film with servo hydraulic control of tire radial load tire slip angle andor slip load tire camber angle road way speed and braking torque A powder spray system is used to prevent rubber buildup on the drum 3M surface The machine was programmed with a drive file that allows for consistent application of energy The machine was run in force control so that the amount of energy input to the tirewheel assembly was consistent between test specimens

Two test methods were conducted one was a 25 percent Fz (radial load) test and the other was a 20 percent Fz test Two tires of each of the six tire models were tested using the 25 percent test One each of the five Phase 1 tire models were tested using the less demanding 20 percent test The tires were of two load indexes and therefore tested using two different load and force levels to match the rolling resistance load differences Table 11 lists these test conditions

Table 11 Test Parameters Item P22560R16 97S 22560R16 98S

Radial Load ndash 80 Max (lbs N) 1287 5725 1322 5882 Camber Angle ( ) 0 0 Speed (mph kmh) 50 80 50 80

Inflation Pressure ( psi kPa) 305 210 305 210 Fy (Lateral) Amplitude ndash 25 (lbs N) 322 1431 331 1471 Fy (Lateral) Amplitude ndash 20 (lbs N) 257 1145 264 1176

Recognizing the historical significance of side force a frictional work or work rate approach was conducted in which the side force was the controlled parameter and was varied throughout the wear test[26] The 25 percent Fz test consisted of 1641 lateral force cycles The input cycle was a sine wave of the following form where Fz is the radial load and t is the time in seconds

1 Fy 25Fz sin t

15 Equation 3 Input Cycle

A similar cycle was used for the 20 percent Fz profile as well except the coefficient was equal to 20 percent Fz Data that was collected as part of the wear testing were tirewheel assembly weight and laser profilometry using a precision scale and a Bytewise CTWIST machine (Figure 12b) The CTWIST machine collects 4096 data points per tire revolution every millimeter across the tire The data was collected at the new or pre-test point at the halfway point and at the end of the test This allows for wear rate to be evaluated

The test sequence required the tire wheel assemblies to be weighed laser-profiled measured for rolling resistance using the proposed ISO 28580 single-point test method and then run on a 400shymile indoor wear cycle The tires were weighed laser-profiled and measured for rolling resisshytance before the final wear cycle of 400 miles was conducted After the final wear cycle the tires were then again weighed laser-profiled and measured for rolling resistance in their final state

Figure 12a MTS 860 Durability Machine Figure 12b CTWIST Machine Figure 12 Indoor Treadwear Equipment

30 RESULTS

31 Effect of Tire Rolling Resistance on Automobile Fuel Efficiency

Fifteen tire models with varying rolling resistance levels were tested on a single vehicle for dyshynamometer fuel economy as previously described Six models were tested at both the placard inflation pressure of 210 kPa and at 158 kPa which represents the TPMS activation threshold of 25 percent inflation pressure loss The effects of tire rolling resistance on vehicle fuel economy are known to be on the scale of fractions of a mile per gallon per pound of rolling resistance Therefore from the outset of the program it was known that the fuel economy tests were atshytempting to measure rolling resistance effects that were at the limits of the accuracy of the test procedure In an attempt to account for this the SRTT (tire type M14) control tires were tested periodically throughout the testing sequence to monitor possible data shifts These may be of two types

1 Shifts in the data due to an event(s) during the approximately four month test proshygram or

2 Drift in the data due to gradual changes in vehicle or dynamometer function

The data is shown in Table 12

Table 12 Test Matrix by Date

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

191 111008 M14 210 1196 217 368 373 364 200 215 111108 B10 210 1211 212 359 372 358 196 220 111208 B12 210 1522 208 354 361 352 194 218 111308 B14 210 1390 211 357 368 359 195 220 111408 D10 210 1356 214 361 371 362 196 220 111708 B15 210 1399 204 358 364 359 193 208 111808 U3 210 1391 210 360 368 363 195 206 111908 G11 210 1002 215 362 371 369 209 222 112008 P5 210 1402 211 357 367 356 215 220 112108 R4 210 1498 209 357 364 214 221 112408 M14 210 1196 217 375 365 219 220 112508 G12 158 1009 Special Tests (Collection Bag Comparison)

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

6 Bold values denote runs with tire types G12 and M14 that were systematically repeated during the testing 7 Rolling resistance values were estimated for 158 kPa tires by adjusting for pressure using regression coefficients from ISO 18164 and SAE J1269 multi-point testing for the tire type

Not Scheduled Mis-Test

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

311 Preliminary Analysis Data Shifts

There were three events identified which corresponded to possible shifts or block events in the data

1 The Highway FET fuel economy cycle was run in triplicate sequentially and showed systematic differences between the runs

2 A shift to significantly higher air conditioning SC03 cycle was noted on November 20 2008 This followed investigation of the differences found in the Highway FET values

3 Physical replacement of the valves and recalibration of the analysis system was comshypleted on January 9 2009

Each period of time was assigned a group number to analyze for differences in data between groups as shown in Table 13

Table 13 Events Identified as Possible Data Shift Correlates

Date Group

Number Description

93008111808

Highway FET cycle was run in triplicate the exhaust gasses for analysis from the runs were collected sequentially into Bag 1 Bag 2 and Bag3

111908 2 The fuel economy lab began a check of the valves and bags to determine if there were mechanical differences

112008 112508

to 3 The air conditioning SC03 cycle data was significantly higher than expected

011309 012309

New valves installed and entire system recalibrated Selected tires were reshyrun on all cycles except Cold City FTP

102108 110608

Cold City FTP cycle ndash initial tire types

120208 121708

Cold City FTP cycle ndash additional tire types

312 Highway FET Triplicate Analysis

The vehicle exhaust gas is routed to a number of bags for collection For the tires in Group 1 the runs for the triplicate analysis of the Highway FET cycle were compared There was a significant difference between the mileage for collection bags with the mileage for bag 2 being approxishymately 07 mpg (2) higher than the values for bags 1 and 3 This is evident in the data shown in Figure 14 The fuel economy lab investigated the mechanical functioning of the system on November 19 2008 and was unable to identify any equipment that was not functioning within specification The decision was made to complete the final group of tires without making any changes to the equipment or procedures Table 14 shows the analysis of variance (ANOVA) for the Highway FET cycle for all tires in groups 1 to 3 On November 25 several runs were made that showed the difference between values correlated to the physical collection bag used in the analysis Six tire types were re-run on the dynamometer in January 2009 after physical replaceshyment of the valves in the system and provided data with equal values from all bags Data for the Highway FET was therefore analyzed by bag Unfortunately this data offset precludes the inshytended use of the Highway FET values to study the precision of the test method

Exhaust Gas amp Ambient Air Sample Collection Bags

Figure 13 Vehicle Fuel Economy Dynamometer Exhaust Collection Bags and Control System

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Figure 14 Highway FET Schedule Fuel Economy Versus Bag Collection Number

Table 14 Analysis of Variance for Highway FET Fuel Economy by Tire Type and Collection Bag Number

Dependent Variable mpg

Source DF Sum of Squares Mean Square F Value Pr gt F

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

Uncorrected Total 76 1006836100

R-Square Coeff Var Root MSE mpg Mean

0925213 0745556 0271294 3638816

Source DF Type III SS Mean Square F Value Pr gt F

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Duncans Multiple Range Test for mpg

Alpha 005

Error Degrees of Freedom 53

Error Mean Square 00736

Harmonic Mean of Cell Sizes 2532468

Means With the Same Letter Are Not Significantly Different

Duncan Grouping Mean N bag

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

313 Air Conditioning SC03 ndash 112008 to 112508

Tire Type M14 (SRTT) was run as a control tire periodically throughout the test procedure The data on November 24 2008 for the SC03 cycle was significantly higher than that seen previshyously as shown in Table 15 The same magnitude of difference was seen in a repeat of the G12 tire at 158 kPa After the replacement of the valves and recalibration of the system was comshypleted on January 9 2009 the data returned to the previous level Figure 15 shows the data for the SC03 cycle by group It is apparent that the data from Group 3 does not follow the trend seen in Group 1 for mpg by rolling resistance of the tire After repair and recalibration of the system the trend for Group 4 returns to nearly that seen in Group 1 No apparent reason for the data shift was seen therefore SC03 data from Groups 2 and 3 were removed from the analysis and tire types G11 P5 and R4 were repeated in Group 4

Table 15 Air Conditioning SC03 Schedule mpg for SRTT Tire by Date

Date G12 Type at 158 kPa

mpg M14 Type at 210 kPa

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Figure 15 Air Conditioning SC03 Fuel Economy Versus Tire Rolling Resistance by Analysis Group

314 Analysis by Date for Possible Drift in Data over Time

Tire types M14 (the SRTT) was repeated systematically during the testing as shown in Table 12 The data for Group 1 or Groups 5 and 6 for the Cold City FTP cycle was analyzed by date of testing to see if there was a drift in the data over time Such a shift could result from systematic changes in the vehicle or dynamometer Table 16 summarizes the results of the analyses Alshythough no individual change in fuel economy is statistically significant the fact that all values seemed to increase slightly over the course of the experiment indicates that there was a slight drift toward higher fuel economy over time For the 50 days of testing in this analysis this would result in a total increase of approximately 05 mpg This means that pair-wise comparisons beshytween tests performed at different times would be suspect For this analysis the only pair-wise comparisons that were studied were between the same tires at different inflation pressures These tests were normally performed on successive days and the greatest difference between tests was 9 days For the overall effect of tire rolling resistance the rolling resistance of the tires studied did not vary systematically over the test period as seen in Figure 16 so this drift will constitute a part of the error term in the analysis

Table 16 Change in Fuel Economy Over Total Time of Testing

Test Probability gt |t| Coefficient mpgday

Highway FET (Bag 1) 0230 00221 Highway FET (Bag 2) 0246 00035 Highway FET (Bag 3) 0779 00045 City FTP 0655 00033 High Speed US06 0098 00095 Air Conditioning SC03 0236 00182 Cold City FTP 0094 00005

Average 00088

ISO 28580 RR lbs

Day Microsoft Date Code

39720 39740 39760 39780 39800 39820 39840

Figure 16 Rolling Resistance of Tires Tested Versus Day of Testing Table 17 summarizes the data that was excluded from the individual analyses of effects on fuel economy based on the preliminary data quality analysis

Table 17 Data Excluded from Fuel Economy Analyses

Test Data Excluded

Highway FET (Bag 1) Group 4 Highway FET (Bag 2) None Highway FET (Bag 3) Group 4 City FTP None High Speed US06 None Air Conditioning SC03 Groups 2 and 3 Cold City FTP None Effect of Inflation Pressure None

Although a number of data quality issues were identified during the fuel economy testing it is important to stress that these problems were accounted for prior to ANOVA analysis Therefore the fuel economy results presented in the report are believed to be accurate as evidenced by there relative agreement with results of similar studies contained in the literature

315 Effect of Tire Rolling Resistance on Fuel Economy

Table 18 shows the results of the analysis of variance for the various fuel economy tests studied Figure 17 through Figure 23 illustrate the trends and 95 percent confidence limits of each test for miles per gallon calculated for four tires of the specified rolling resistance mounted on the vehi-cle versus the rolling resistance force values for the tires studied Although the R2 values are poor the tire rolling resistance term is significant and the F Values indicate that the overall trend toward lower fuel economy with increasing tire rolling resistance is statistically significant Val-ues of Probability |t| less than 005 indicate that the variable (lbf) has a significant effect on roll-ing resistance Figure 24 shows the fuel economy as a percentage of the mean for each test ver-sus the rolling resistance as a percentage of the mean rolling resistance The scatter in the data is evident but the overall trends are clear and the percentage decreases in fuel economy as tire roll-ing resistance increases show very similar trends Previous studies have shown the effects of roll-ing resistance as percentage change in mileage for the vehicle (mpg) that results from some percentage change in rolling resistance of the tires (Rolling Resistance) Table 19 shows the regression results for this measure The increase in mpg for a 10 percent decrease in rolling resis-tance is approximately 11 percent ranging from a low of 08 percent for the air conditioning SC03 cycle to a high of 13 percent for the High-Speed US06 cycle These results agree with the calculated values of a 07 percent to 20 percent change in fuel economy for a 10 percent change in rolling resistance that are shown in the Transportation Research Board Special Report 286[27]

Table 18 ANOVA Results for Effect of Tire Rolling Resistance on Fuel Economy

Test F Value Probability

gt F R2 Value

Coefficient mpg lbf Rolling Resistance

Probability gt |t|

Highway FET (Bag 1) 462 00001 0687 -0306 00001 Highway FET (Bag 2) 715 00001 0695 -0315 00001 Highway FET (Bag 3) 755 00001 0770 -0376 00001 Average Highway FET -0332 City FTP 485 00001 0593 -0176 00001 High Speed US06 486 00001 0611 -0233 00001 Air Conditioning SC03 160 00005 0381 -0131 00005 Cold City FTP 457 00001 0729 -0168 00001 Table 19 Percentage Change in Fuel Economy Versus Percentage Change in Tire Rolling

Resistance Coefficient

Test mpg Rolling Resistance

Variability CV

Highway FET (Bag 1) -0105 113 Highway FET (Bag 2) -0106 115 Highway FET (Bag 3) -0127 108 Average Highway FET -0113 112 City FTP -0102 140 High Speed US06 -0132 177 Air Conditioning SC03 -0083 178 Cold City FTP -0112 107

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Figure 17 Highway FET (Bag 1) Mileage Versus Tire Rolling Resistance

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Figure 20 City FTP Mileage Versus Tire Rolling Resistance

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Figure 21 High Speed US06 Mileage Versus Tire Rolling Resistance

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Figure 22 Air Conditioning SC03 Mileage Versus Tire Rolling Resistance

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Figure 23 Cold City FTP Mileage Versus Tire Rolling Resistance

Rolling Resistance

80 90 100 110 120 130

1 = Highway FET (Bag 1) 2 = Highway FET (Bag 2) 3 = Highway FET (Bag 3)

4 = City FTP 7 = Cold City FTP 5 = High Speed US06 6 = Air Conditioning SC03

Figure 24 Percentage Change in Fuel Economy Versus Percentage Change in Tire Rolling Resistance

316 Effect of Reduced Inflation Pressure on Fuel Economy

Underinflated tires have been shown to be a prevalent issue for passenger vehicle safety In 2001 NHTSA released the results of the Tire Pressure Special Study showing that 28 percent of passenger cars had at least one tire underinflated by 8 psi or more[28] Recently NHTSA pubshylished the results of a sample of vehicles surveyed with and without tire pressure monitoring sysshytems (TPMS)[29] Although the number of vehicles with underinflated tires was less with TPMS there were still approximately 20 percent of vehicles equipped with TPMS systems that had at least one tire underinflated by 25 percent or more8 While the primary safety issue for unshyder-inflation of tires is reduced vehicle control and possible tire failure due to cumulative damshyage studies have shown that underinflation increases the rolling resistance of a tire thus increasshying vehicle fuel consumption

Using available literature (1991) Wicks and Sheets assumed that the rolling resistance of a tire increased inversely with the ldquounder pressurerdquo ratio (actual tire pressure divided by the recomshymended tire pressure) Using a theoretical drop in pressure from 35 psi (241 kPa) to 25 psi (172

8 For those vehicles equipped with direct TPMS there were approximately 1 percent with at least one tire underinshyflated by 25 percent or more

kPa) they estimated a 384 percent increase in vehicle fuel consumption for a 10 psi reduction in tire inflation pressure[30] The US Department of Energy predicts an increase in fuel consumpshytion of 3 percent for each 10 psi reduction in tire pressure[31] Clark et al show increases in rollshying resistance of 1 percent to 3 percent for each psi reduction in inflation pressure[32] Hall and Moreland show increases in rolling resistance of 1 to 2 percent for a 1 psi reduction in inflation pressure [33] and Continental Tire shows an increase in rolling resistance of 16-percent per psi reduction in rolling resistance[34] Using the NAS predictions of a 1- to 2-percent decrease in fuel consumption for a 10 percent increase in rolling resistance the predicted values in mpgpsi is shown in Table 20

In 1981 the US Environmental Protection Agency published an SAE paper on the effects of reduced inflation pressure on fuel mileage measured during on-road vehicle testing[35] The testshying used two identical 1979 Chevrolet Nova passenger cars with the OEM radial tires The two vehicles were simultaneously driven on a closed test track through repetitive cycles of the then current EPA Urban and Highway driving schedules The vehicles had a placard tire pressure of 24 psi (165 kPa) and all four tires on the vehicle were either adjusted up or down by 4 psi (28 kPa) from the placard The 8-psi (55-kPa) difference in tire pressure generated an average comshyposite9 fuel consumption to tire pressure change ratio of 033psi

Table 20 Predicted Change in Fuel Economy for 1 psi Change in Tire Inflation Pressure Study Predicted Reduction

mpgpsi Calculation Notes

Wicks and Sheets 038 38mpg10psi

US Department of Energy 03 3pmg10psi

Clark et al 01 to 06 1mpg10RR1RRpsi to 2mpg10RR3RRpsi

Hall and Moreland 01 to 04 1mpg10RR1RRpsi to 2mpg10RR2RRpsi

Continental Tire 016 to 032 1mpg10RR16RRpsi to 2mpg10RR16RRpsi

US EPA 033 Measured in on-vehicle tests published 1981

Average 0308

Referencing Schuringrsquos work in 1980 LaClair states[36]

ldquoWhen a tire is under-inflated its rolling resistance increases by a factor of on average about (PP0)

-04 where P0 is the specified inflation pressurerdquo

Per this relationship a (158210)-04 or 12 percent increase in rolling resistance should be obshyserved Also referencing Schuring NAS states[37]

9 Composite fuel cycle was weighted for 55 percent urban cycles and 45 percent highway cycles

ldquoSchuring (1980) observes that for conventional passenger tires an increase in inflation pressure from 24 to 29 pounds per square inch (psi) will reduce rolling resistance by 10 percent For a tire inflated to pressures between 24 and 36 psi each drop of 1 psi leads to a 14-percent increase in its rolling resistancerdquo

Per this relationship a 10-percent increase (30-23 psi = 7 psi 14psi = 10 ) in rolling resisshytance should be observed

The effect of reduced inflation pressure was estimated from comparison of the dynamometer fuel economy of the vehicle with the front tires inflated to the placard pressure of 210 kPa (30 psi) to tests with the same front tires inflated to 158 kPa (23 psi) The lower pressure represents the 25 percent reduced pressure activation threshold of the tire pressure monitoring system (TPMS) specified in FMVSS No 138 Six tire models that spanned the range of rolling resistances were chosen for the experiment Unlike on-road vehicle operation tests on the indoor fuel economy dynamometer involve only the driven axle(s) of the vehicle which for the Chevy Malibu test veshyhicle was the front axle Since the EPA fuel economy test is completed using only the driven axle it is assumed that the effects of the drag of the non-driven axle (rear axle) on vehicle fuel economy are accounted for in the EPArsquos complex equations Therefore it is also assumed that the increased rolling resistance of the front tires due to underinflation will scale up through these equations to the effects of four underinflated tires on vehicle fuel economy However no on-road testing was completed to confirm this

Statistical pair-wise comparisons of the same tires tested at the two different inflation pressures did not show significant differences in fuel economy However there was a trend for tires at the lower inflation pressure to generate lower fuel economy in all tests as shown in Figure 26 to Figure 32 which illustrates the data by tire type where the ldquoLrdquo suffix (eg M14L) indicates the 158-kPa inflation pressure Table 21 shows the results of the ANOVA analysis for the tests All but one of the tests showed a decrease of 03 to 05 miles per gallon for all fuel economy cycles for the 25-percent decrease in tire pressure The High Speed US06 test showed no significant change in fuel economy

Using the relationship between rolling resistance and fuel economy for the vehicle tested by NHTSA as shown in Table 19 a 011-percent reduction in fuel economy is predicted for each 1 percent increase in rolling resistance Based on LaClairrsquos estimate of rolling resistance increases of 12 percent for the reduced pressure a 13-percent reduction in overall fuel economy for all cycles is predicted Therefore the actual results in Table 21 of an approximate 117-percent reshyduction in overall fuel economy for all cycles is fairly close to the 13-percent prediction The predicted value using the NAS estimate of a 11-percent decrease in fuel economy is also very close to the measured value of 117 percent

However the measured fuel economy of the vehicle at reduced inflation pressure was signifishycantly less than the average predicted value shown in Table 20 When weighted in the same manner as used by the EPA the results for the Urban and Highway cycles in Table 19 predict fuel consumption to tire pressure change ratio of 011 percentpsi or about a third of that seen by the EPA on the track in 1979 The following explanations or combinations of the following are thought to be possible

1 The effects of underinflation on the tire contact patch that would occur with a tire on a relatively flat road may not approximated by the Hertzian-like contact of the tire on the curved 48-inch diameter steel rollers of the fuel economy dynamometer (Figure 25)

2 The increased heat build-up of the low inflation tires on the dynamometer rollers which could raise the inflation pressure significantly over the short duration of the test and lower the differential in rolling resistance between the under-inflated and properly inshyflated tires

3 Assuming a nominal load on the tires of 80 percent of maximum sidewall the predicted 10 percent increase in rolling resistance due to 25 percent underinflation for the highest rolling resistance tire model in the study (type B12) is 1522 lbf x 01 x 2 tires = +30 lbf for two tires on the front axle For the lowest the OE type G12 tires it is 947 x 01 x 2 tires = +19 lbf In horsepower terms at the 60 mph speed of the highway test cycle the increased rolling resistance forces are roughly 03-05 hp on a vehicle with an engine rated at 211 hp at 5800 rpm or only 014-024 percent of maximum horsepower The veshyhiclersquos modern fuel ignition and powertrain management software which may include adaptive spark timing adaptive exhaust catalyst mass-airflow sensors and other techshynologies to lessen emissions and optimize fuel economy may mitigate some of the efshyfects of the additional rolling resistance of the two underinflated tires at the front axle This is particularly significant when comparing these results to earlier results using carshybureted vehicles For instance the carbureted 1979 Chevrolet Nova vehicles used in the EPA testing were rated at 115 maximum horsepower at 3800 rpm

4 The dynamometer loading is dependent on the road load coast-down coefficients of the vehicle with the OE tires at placard cold inflation pressure This in turn affects the emisshysions results and therefore the fuel economy of the vehicle New road load coast-down coefficients may have to be determined for vehicle tests at the lower TPMS activation pressure

Figure 25 Tire to Dynamometer Roller Contact 2008 Chevrolet Impala LS Engine

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

Figure 26 Highway FET (Bag 1) Fuel Economy by Tire Type and Inflation Pressure

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

Figure 29 City FTP Fuel Economy by Tire Type and Inflation Pressure

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

Figure 30 High Speed US06 Fuel Economy by Tire Type and Inflation Pressure

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

Figure 31 Air Conditioning SC03 Fuel Economy by Tire Type and Inflation Pressure

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

Figure 32 Cold City FTP Fuel Economy by Tire Type and Inflation Pressure

Table 21 ANOVA Results for Effect of Tire Inflation Pressure Reduction on Fuel Economy

Test Coefficient Probability

gt |t|mpg 52 kPa mpg kPa mpg psi Highway FET (Bag 1) -0553 -0030 -0203 00119 Highway FET (Bag 2) -0173 -0009 -0062 00164 Highway FET (Bag 3) -0206 -0011 -0075 00092 Average Highway FET -0311 -00167 -0113 00125 City FTP -0166 -0015 -0103 00008 High Speed US06 -0018 -0001 -0011 08200 Air Conditioning SC03 -0497 -0049 -0337 00096 Cold City FTP -0305 -0031 -0216 00088

317 Fuel Economy Testing Summary

The repeatability of the fuel economy tests were found to range from 1 to 2 percent Using a brand new vehicle with mileage break-in to the prescribed 2000 miles a significant upward drift in the average mpg between 2000 and 6000 miles was noted Offsets between the intended triplicate Highway FET results precluded a more precise assessment of the accuracy of the test In spite of these limitations there was a significant effect of tire rolling resistance on fuel econshyomy for all tests over the 947 to 1560 pound range of the tires studied For all tests a 10 percent decrease in rolling resistance resulted in slightly more than a 1 percent increase in fuel economy for the vehicle Reducing the inflation pressure by 25 percent resulted in a small but statistically significant decrease in the fuel economy of the vehicle by approximately 03 to 05 miles per galshy

lon for all tests except the high-speed high-acceleration US06 cycle Figure 33 illustrates the trends for the Highway FET (Bag 2) test As before the suffix of ldquoLrdquo for the tire type indicates the low-pressure condition The trend to lower mileage with increased rolling resistance is clear In general the tires at lower inflation pressure have lower gas mileage in line with their calculatshyed10 rolling resistance at the reduced pressure

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Figure 33 Highway FET (Bag 2) Fuel Economy Versus Tire Rolling Resistance by Tire Type and Inflation Pressure

32 Correlation of Tangent δ at 60degC to Tire Rolling Resistance

The tread compounds of 16 tire models were tested for dynamic mechanical properties Literashyture has suggested that the tangent δ at 60degC correlates to the treadrsquos contribution to the rolling resistance of a tire The Pearson R product moment correlation of the measures for the 16 tires is shown in Table 22 The measured rolling resistance has a significant positive correlation of 072 to the tangent δ measured in both shear and tension The measures in shear and tension are very highly correlated The data for rolling resistance versus tangent δ measured in tension by tire type is shown in Figure 34 It appears that the data falls into two groups of tangent δ which strongly influences the overall correlation However the low tangent δ and low rolling resistance group consists of two tire brands Interestingly these three tire types shown in the lower left corshyner of the graph have all been confirmed by their manufacturers as being original equipment tires models Table 23 shows the correlation of rolling resistance to some compound properties and

10 Calculated from the coefficients of the multi-point rolling resistance tests of those tire types

how they differ for two brands of tires Both the Bridgestone and Goodyear tires individually show a stronger correlation of rolling resistance and tangent δ at 60degC than that shown for all tires grouped together The differing correlations to compound properties may be related to difshyfering compound strategies of the companies to tailor compounds for individual tire performshyance The Bridgestone tires seem to be sensitive to increases in the total filler level while the Goodyear tires seem to be more sensitive to the type of filler (percent silica) and possibly to other compounding ingredients (volatile content) A broad range of tire types were measured for compound properties and rolling resistance and will be reported separately

Table 22 Correlation of Rolling Resistance to Tangent δ at 60degC Correlation to Rolling Resistance

Tan degCgent δ at 60 (Tension)

Tang 0degCent δ at 6 (Shear)

07216 07311 Probability gt |r| 00016 lt00001

Rolling Resistance

Tangent delta 60C in Tension

006 008 010 012 014 016 018 020 022

Figure 34 ISO 28580 Rolling Resistance (lbs)Versus Tangent δ at 60degC by Tire Type OE Tires

OE Run-Flat Tire

Table 23 Correlation of Properties to Rolling Resistance Correlation to Rolling Resistance Parameter

All Tires Bridgestone Tires Only Goodyear Tires Only Tangent δ at 60degC (tension) 0722 0901 0932 Percent Polymer in Compound -0816 -0920 -0598 Percent Volatiles in Compound 0645 0828 0912 Total Filler Level of Compound 0814 0907 0341 Percent of Filler That is Silica -0109 -0068 -0945

33 Effect of Tire Rolling Resistance on Safety

Sixteen tire models representing a range of rolling resistance and of other characteristics were tested for both dry and wet traction by NHTSA The testing was done in conjunction with the standard ASTM E501 Standard Reference Test Tire used for UTQGS testing The FMVSS 575104 UTQGS Traction grade is based upon the wet slide traction coefficient which is ad-justed with results from the ASTM E501 tire to correct for variations in the test surface envi-ronmental conditions etc Since the standard does not have a procedure for adjusting wet peak or dry peak and slide traction coefficients it was decided to report raw traction data as ldquoTraction Numberrdquo (coefficient of friction x 102) and as a ldquoRatio to the Course Monitoring Tirerdquo (ASTM E501) The ratios were calculated using the only results from the E501 course monitoring tires used for that tire modelrsquos traction testing sequence In this manner the ratios represent data that has been ldquocorrectedrdquo for variations in the test surface environmental conditions etc The wet slide data is reported in this same format as well as in the form of the UTQGS adjusted traction coefficient Since these tires were previously tested for rolling resistance and did not undergo the full break-in period the results for the adjusted traction coefficients are unofficial The raw peak and slide traction data for dry and wet asphalt and concrete testing as well as adjusted UTQGS wet slide coefficients are contained in Appendix 4 through Appendix 10

331 Dry Traction Data

Table 24 shows the average dry traction results for each tire type on asphalt and concrete Table 25 shows the Pearson Product Moment Correlation of the values for dry traction to the tire roll-ing resistance The Pearson value indicates the strength and direction of the correlation with val-ues ranging from -1 for complete inverse correlation to +1 for complete direct correlation with values near zero indicating no correlation between the measures It is evident that there is very little correlation between the traction and rolling resistance for these tires For a value to be sta-tistically significant the probability gt |r| would have to be less than 0050 and no value ap-proaches that number Figure 35 and Figure 36 display clearly that there is no indication that a tire with improved rolling resistance will necessarily have lower dry traction performance in this test

Table 24 Dry Traction Results Traction Number and Ratio to E501 Reference Tire Tire Type

ISO 28580 Rollshying Resistance

Traction Asphalt Concrete

Peak Value Sliding Value Peak Value Sliding Value Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

Table 25 Pearson Product Moment Correlation of Dry Traction to Rolling Resistance

Correlation to ISO 28580 Rolling Reshy

sistance

Pearson Product Moment Correlation Asphalt Dry Traction Concrete Dry Traction

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

Figure 35 Dry Traction Numbers Versus ISO 28580 Rolling Resistance

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

ISO 28580 Rolling Resistance (lbs)

Concrete - Peak Number

Asphalt - Peak Number

Concrete - Slide Number

Asphalt - Slide Number

Figure 36 Dry Traction Ratios to E501 Course Monitoring Tire Versus Rolling Resistance

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Asphalt - Slide Ratio

Concrete - Slide Ratio

Asphalt - Peak Ratio

Concrete - Peak Ratio

332 Wet Traction Data

Table 26 shows the average wet traction results for each tire type on asphalt and concrete Table 27 shows the Pearson Product Moment Correlation of the values for wet traction to the tire rollshying resistance The Pearson value indicates the strength and direction of the correlation with valshyues ranging from -1 for complete inverse correlation to +1 for complete direct correlation with values near zero indicating no correlation between the measures For a value to be statistically significant the probability gt |r| should be less than 0050 The sliding values all have a strong and significant relationship between better rolling resistance and poorer wet traction The peak values display the same tendency but the relationship is much weaker

Figure 37 and Figure 38 display these trends graphically for the traction numbers and the ratio to the E501 monitoring tire respectively From these data it appears that the tires with lower rolling resistance values will have poorer wet traction performance in the sliding region This will be particularly significant to consumers without ABS systems on their vehicles since the sliding value will relate most closely to emergency stopping maneuvers In contrast the results for the measured wet peak traction number in the same figures exhibit much less pronounced trends Hence for newer vehicles with ABS or ESC systems the tradeoff is expected to be much less significant

Table 26 Wet Traction Results Traction Number and Ratio to E501 Reference Tire

Tire Type

ISO 28580 Rolling Reshysistance lbs

Wet Traction Asphalt Concrete

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Table 27 Pearson Product Moment Correlation of Wet Traction to Rolling Resistance

Correlation to ISO 28580 Rolling Resistance

Pearson Product Moment Correlation

Asphalt Wet Traction Concrete Wet Traction

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0299 0391 0739 0725 0465 0473 0700 0628 Probability gt |r| 00965 00270 lt0001 lt0001 0007 0006 lt0001 0001

Figure 37 Wet Traction Numbers Versus ISO 28580 Rolling Resistance

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

Figure 38 Wet Traction Ratios to E501 Course Monitoring Tire Versus Rolling Resistance

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

333 UTQGS Traction Grade

As stated earlier the FMVSS 575104 UTQGS Traction grade is based upon the adjusted traction coefficient which is calculated from the candidate tirersquos wet slide coefficient of friction and the standard reference tirersquos wet slide coefficient of friction using the following procedure

Average the 10 measurements taken on the asphalt surface to find the candidate tire tracshytion coefficient for the asphalt surface Average the 10 measurements taken on the conshycrete surface to find the candidate tire traction coefficient for the concrete surface

(ix) Compute a candidate tirersquos adjusted traction coefficient for asphalt (μa) by the following formula

μa = Measured candidate tire coefficient for asphalt + 050 - Measured standard tire coefficient for asphalt

(x) Compute a candidate tirersquos adjusted traction coefficient for concrete (μc) by the following formula

μc = Measured candidate tire coefficient for concrete +035 μMeasured standard tire coefficient for concrete

The results for the UTQGS Adjusted Traction Coefficient (unofficial) on asphalt verses the rollshying resistance of the tire as measured by ISO 28580 are presented in Figure 39 The limits for the three grades within the span of the test tires are indicated on the figure Similar to the raw wet traction trailer data the adjusted traction coefficient on asphalt was lower in lower rolling resisshytance tires

Figure 39 UTQG Adjusted Traction Coefficient for Asphalt Versus ISO 28580 Rolling Resistance

R2 = 05175

9 10 11 12 13 14 15 1

The results for the UTQGS Adjusted Traction Coefficient (unofficial) on concrete verses the rolling resistance of the tire as measured by ISO 28580 are presented in Figure 40 The limits for the three grades within the span of the test tires are indicated on the figure Again similar to the raw wet traction trailer data the adjusted traction coefficient on concrete was lower in lower rollshying resistance tires

Figure 40 UTQG Adjusted Traction Coefficient for Concrete Versus ISO 28580 Rolling Resistance

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

334 Correlation of Tangent δ at 0degC to Wet Traction Properties

Literature has shown a general trend towards increased wet traction properties of tires as the tanshygent δ at 0degC of the tread compound increases Table 28 shows the Pearson correlation coeffishycient between the measured slide numbers for wet traction and the tangent δ at 0degC of the tread compound measured in tension There is a strong positive correlation of the tangent δ at 0degC to wet traction of the tires particularly for the sliding values The data for the slide number on conshycrete versus tangent δ at 0degC is shown in Figure 41 This relationship appears to be more genershyally applicable than that seen for rolling resistance to tangent δ at 60degC

Slide Number Concrete

016 018 020 022 024 026 028 030 032 034 036 038 040

Figure 41 Slide Traction Number on Wet Concrete Versus Tangent δ at 0degC Measured in Tension

OE Tires OE Run-Flat Tire

Table 28 Pearson R Product Moment Correlation of Wet Traction to Tangent δ at 0degC of the Tread Compound

Correlation to Tangent δ at 0degC (Tenshy

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

34 Effects of Tire Rolling Resistance on Treadwear Rate

As was seen previously there was not a good correlation between the rolling resistance and the UTQGS treadwear grade of the tires studied Four tire models that were selected to represent the range of rolling resistance of the models studied along with the SRTT (tire type M14) were tested according to the UTQGS testing protocol for treadwear Although these tires were previshyously tested for rolling resistance in a laboratory the wear rates and projected mileages are exshypected to be similar to those for new tires of the same model Measurements were taken across

Coefficient of Variation

the tire at six locations in each groove (1 through 4) Data were analyzed by tire type by groove by shoulder (groove 1amp4) or tread center (groove 2amp3) General observations are shown in Table 29 for each tire type The coefficients of variation for the wear rates are approximately 05 percent for all tire types indicating that comparisons between tire types at these conditions are reliable Models for the wear rate against course mileage produced R2 values of 094 to 097 for linear models and 098 to 099 for quadratic models For all tire types except B13 the quadratic term was statistically significant indicating that the wear rate tends to change (either increase or decrease) as the tire wears

Table 29 Analysis of Tire Wear Data Tire Type

Groove 1 to 4 Shoulder Versus Tread Center

Non-Linear Behavior

B11 030 Groove 1 shows faster wear rate11

Shoulder wear rate faster than tread center

Wear rate tends to increase

B13 044 - Similar wear rates No change in wear rate

G8 051 Groove 4 shows slower wear rate12

Similar wear rates Wear rate tends to increase

M13 054 - Tread center wear rate faster than shoulder

Wear rate tends to decrease

Table 30 shows the treadwear rates and projected mileage to 232nds tread depth for the tires For each model the wear rates for the shoulder and tread center were compared along with the proshyjected lifetime for each area For tire type B11 the wear rate in the shoulder area was signifishycantly faster than the wear rate in the tread center with a corresponding decrease in projected mileage For tire type M14 the wear rate in the tread center was significantly faster than in the shoulder area with significantly shorter projected tread life in this area Tire type M13 had faster wear rates in the tread center but this was partially offset by a lesser groove depth in the shoulder area in projecting tire lifetime

Figure 42 shows the projected average tire mileage to wear out and the minimum projected mileshyage versus the rolling resistance for the tire From these data there is no relationship between expected tire lifetime and rolling resistance Since the tread depth may affect both rolling resisshytance and tire lifetime the average wear rate and the fastest wear rate either from the shoulder or tread center area was compared to the rolling resistance It is evident from Figure 43 that there is no clear relationship between wear rate and rolling resistance for these tires In summary there is no evidence from this data that a tire with reduced rolling resistance will necessarily have reshyduced tread life

11 Data was influenced by high wear rate of tire 3146 The other B11 tires showed no anomalous behavior for indishyvidual grooves12 All type G8 tires showed anomalous behavior for groove 4

Table 30 Wear Rates and Projected Mileage to 232nds Tread Depth From UTQGS Treadwear Course

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Figure 42 Projected Tire Mileage to Wearout (Average and Minimum) Versus ISO 28580

Rolling Resistance

UTQG Course Wear Versus Rolling Resistance

9 10 11 12 13 14 15 16

ISO 28580 Rolling Resistance pounds

Average Miles

Minimum Miles

Figure 43 Average and Fastest Treadwear Rate Versus ISO 28580 Rolling Resistance

Wear Rates Versus Rolling Resistance

9 10 11 12 13 14 15 16

Average

Fastest

341 Analysis of Wear Data From Indoor Treadwear Testing

Four tire models which were selected to represent the range of rolling resistance of the models studied along with the SRTT (Type M14) and the original equipment tires from the Chevrolet Impala used in the fuel economy testing (Type G12) were tested using an experimental protocol for indoor treadwear testing While the computerized data acquisition provides 3-dimensional measurements of the tire profile as shown in Appendix 3 representative measurements at 400 and 800 miles of wear were taken across the tire at six locations the inside shoulder the outside shoulder and at each of the 4 tread grooves The average data for the models is shown in Appendix 3 Tires were tested in duplicate at a severe condition and for five of the models a third tire was tested at a milder wear condition Data was analyzed by tire type by groove by shoulder or tread center and by wear severity

General observations are shown in Table 29 for each tire type Although all tires tended to show somewhat faster wear in the shoulder region than at the tread center tire type B11 showed wear rates more than 3 times faster in the shoulder region than at the tread center This tire type also showed significantly faster wear rates in the shoulder area in the UTQGS course testing As exshypected the wear rates at the severe condition were two to three times faster than at the mild conshy

dition The loss per mile on this test was 3 to 20 times the wear rates that the same model tires experienced on the UTQGS testing course

Table 31 Indoor Treadwear Tire Wear Data Average Wear Rate

mils1000 miles Shoulder Versus Tread Center

Wear Rate ratio Tire Type

Severe Condition Mild Condition Severe Condition Mild Condition

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

Table 30 shows the projected tire lifetime for severe and mild conditions calculated for both the shoulder and tread center region of the tires All tires had the shortest predicted lifetime in the shoulder area For the severe wear condition this ranged from 1250 miles for tire type B11 and G8 to 5500 miles for tire type M13 At the mild condition the projected lifetime was two to three times that of the severe condition Figure 42 shows the projected tire lifetime versus rolling resistance for the tire types and Figure 45 shows the wear rate versus tire rolling resistance Both indicate that there is a trend toward faster wear on this test for tires with lower rolling resistance The ANOVA analysis shown in Table 33 to Table 36 indicates that the relationship between lower rolling resistance and lower expected tread life is statistically significant for this test This relationship is stronger for the projected lifetime based on the wear at the tread center as evi-denced by the R2 values of 075 to 08 Each decreased pound of original tire rolling resistance correlates to approximately 1000 miles of reduced wear at the mild condition and 2000 miles at the severe condition

Table 32 Projected Mileage to 232nds Inch of Tread Depth Projected Tread Life miles

Severe Condition Mild Condition Tire

ISO 28580 Rolling Resistance lbsType

Tread Center Shoulder Tread Center Shoulder G12 947 5156 2035 NA NA G8 983 4137 1264 9200 5327 B11 1013 4412 1260 12842 4613 M14 1196 7732 4937 17476 8738 M13 1207 8432 5717 15648 12000 B13 1501 10902 4440 20628 9114

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Figure 44 Projected Tire Lifetime for Indoor Treadwear Test Versus ISO 28580 Rolling Resistance

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Figure 45 Treadwear Rate for Indoor Treadwear Test Versus ISO 28580 Rolling Resistance

Table 33 Projected Lifetime Versus Rolling Resistance ndash Mild Wear at Tread Center

Dependent Variable Projected Lifetime at Tread Center Wear Condition=Mild

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

Corrected Total 4 7640668321

R-Square Coeff Var Root MSE clife Mean

0801276 1484057 2249727 1515930

Rolling Resistance 1 6122287064 6122287064 1210 00401

Parameter Estimate Standard Error t Value Pr gt |t|

Intercept -9197417585 7075025908 -130 02845

Rolling Resistance 2045064795 588003644 348 00401

Table 34 Projected Lifetime Versus Rolling Resistance ndash Severe Wear at Tread Center

Dependent Variable Projected Lifetime at Tread Center Wear Condition=Severe

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Table 35 Projected Lifetime Versus Rolling Resistance ndash Mild Wear at Shoulder

Dependent Variable Projected Lifetime at Shoulder Wear Condition=Mild

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

R-Square Coeff Var Root MSE slife Mean

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Table 36 Projected Lifetime Versus Rolling Resistance ndash Severe Wear at Shoulder

Dependent Variable Projected Lifetime at Shoulder Wear Condition=Severe

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

Rolling Resistance 602385393 262239764 230 00472 Figure 46 shows the projected tread life for the tires versus the UTQGS tread grade There is no clear relationship between the UTQGS number and the projected tread life on this test

250 350 450 550 650 750

UTQGS Treadwear Grade

read Severe

Figure 46 Projected Tire Lifetime for Indoor Treadwear Test Versus UTQGS Treadwear Grade

Change in Rolling Resistance Versus Tire Wear The rolling resistance of each tire was measured using the ISO 28580 test procedure All tires were measured prior to beginning the testing At the severe wear condition the tires were also measured after 400 miles and at the end of the 800-mile test At the mild wear condition the tires were measured at the end of the 800-mile test Tires were also weighed prior to the rolling resisshytance test and after 400 and 800 miles of wear The data is shown in Appendix 3 Figure 47 shows the rolling resistance versus the weight of the tires Some tires such as type G12 and B11 seem to show consistent decreases in rolling resistance with tread loss and there seems to be a tendency for lighter tires to have lower rolling resistance However many tires show no clear relationship between tread loss and rolling resistance for this testing Figure 48 shows the rolling resistance as a percent of the original value for each tire versus the weight loss during the testing A slight reduction in rolling resistance may be observed however the change is less than the scatter of the data on the order of 1 percent to 2 percent change for a 1-pound loss of tread comshypound

Table 37 shows the ANOVA analysis of the data for rolling resistance loss versus weight loss and heel-to-to wear value for the tires Heel-to-toe wear is a more significant term than weight loss but the overall trend is still within the scatter of the data Figure 49 shows the percentage of the original rolling resistance versus the weight loss and heel-to-to wear As expected from the low R2 value of 013 the scatter in the data is too great to draw conclusions about the effects of these changes on rolling resistance All data is within 6 percent of the original rolling resistance so neither term has a significant effect on the rolling resistance

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Figure 47 ISO 28580 Rolling Resistance Versus Tire Weight Loss

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Figure 48 Rolling Resistance as Percent of the Original Rolling Resistance Versus Tire Weight Loss During Testing

Table 37 Analysis of Rolling Resistance Change Versus Weight Loss and Heel-to-Toe Wear

Dependent Variable Rolling Resistance as a Percent of New Tire

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

R-Square Coeff Var Root MSE rr Mean

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Change in Heel-to-Toe Wear 1 600659293 600659293 157 02174

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

Change in Heel-to-Toe Wear -107151522 085540108 -125 02174

016 065

115 164

Weight Loss lbs -180

ht 9384

Figure 49 Percentage of Original Rolling Resistance Versus Weight Loss and Heel-to-Toe Wear Change

40 CONCLUSIONS

Based on five different fuel economy cycles a 10 percent decrease in tire rolling resistance reshysulted in approximately 11 percent increase in fuel economy for the vehicle This result was within the range predicted by technical literature Reducing the inflation pressure by 25 percent resulted in a small but statistically significant decrease of approximately 03 to 05 miles per galshylon for four of the five fuel economy cycles excluding the high-speed high-acceleration US06 cycle This value was smaller than many values predicted by technical literature and possible explanations are being explored

For the tires studied there appeared to be no significant relationship between dry peak or slide numbers and rolling resistance However these tire models exhibited a strong and significant relationship between better rolling resistance and poorer wet slide numbers The peak wet slide number displayed the same tendency but the relationship was much weaker This may be sigshynificant to consumers without anti-lock braking systems (ABS) on their vehicles since the wet slide value relates most closely to locked-wheel emergency stops For newer vehicles with ABS or electronic stability control systems which operate in the lower slip and higher range of wet peak friction the tradeoff is expected to be less significant

For the subset of five tire models subjected to on-vehicle treadwear testing (UTQGS) no clear relationship was exhibited between tread wear rate and rolling resistance levels For the subset of six tire models subjected to significant amounts of wear in the indoor treadwear tests there was a trend toward faster wear for tires with lower rolling resistance

50 REQUIREMENTS

The Energy Independence and Security Act of 2007 specified in SEC 111 Consumer Tire Inshyformation that the Secretary of Transportation shall after notice and opportunity for comment promulgate rules establishing a national tire fuel efficiency consumer information program that includes

(A) a national tire fuel efficiency rating system for motor vehicle replacement tires to asshysist consumers in making more educated tire purchasing decisions (B) requirements for providing information to consumers including information at the point of sale and other potential information dissemination methods including the Intershynet (C) specifications for test methods for manufacturers to use in assessing and rating tires to avoid variation among test equipment and manufacturers and (D) a national tire maintenance consumer education program including information on tire inflation pressure alignment rotation and tread wear to maximize fuel efficiency safety and durability of replacement tires

The recommendations of the technical staff will therefore be summarized per each specific reshyquirement

(A) A national tire fuel efficiency rating system for motor vehicle replacement tires to assist consumers in making more educated tire purchasing decisions

Phase 1 of the project showed that the current laboratory rolling resistance test methods provide an objective and repeatable basis for measuring the energy loss per unit distance traveled for a given tire at a set of nominal operating conditions This energy loss requires the vehicle to supply additional torque to the rotating tire and directly reduces the efficiency of a vehicle in converting the chemical energy in the fuel to motion of the vehicle Therefore tire rolling resistance is the most effective metric for rating the ldquofuel efficiencyrdquo of a tire13

(B) Requirements for providing information to consumers including information at the point of sale and other potential information dissemination methods including the Internet

The output of a laboratory rolling resistance test either rolling force in units of N or lbf or rollshying resistance coefficient in NkN kgtonne or lbfkip will be difficult for consumers to undershystand and relate to vehicle fuel economy These measures must be communicated in a more conshysumer friendly format

13 It should be noted that Schuring defines ldquotire efficiencyrdquo as the ratio of tire output to tire input energy In the case of a tire measured on a rolling resistance test machine the ldquotire efficiencyrdquo of the free-rolling tire (zero slip - steady state speed) is technically zero Schuring D J amp Futamura S (1990) Rolling Loss of Pneumatic Highway Tires in the Eighties Figure 7 Rubber Chemistry and Technology Vol 62 No 3 pp 315ndash367

(C) Specifications for test methods for manufacturers to use in assessing and rating tires to avoid variation among test equipment and manufacturers

Phase 1 of the project showed that all five of the rolling resistance test methods evaluated had very low variability and all methods could be cross-correlated to provide the same information about individual tire types It was concluded that while multi-point rolling resistance test methshyods are necessary to characterize the response of a tirersquos rolling resistance over a range of loads pressures andor speeds either of the two shorter and less expensive single-point test methods were sufficient for the purpose of simply assessing and rating individual tires in a common sysshytem The single-point ISO 28580 was preferable to the single-point SAE J1269 method since the former contains a lab-to-lab measurement result correlation procedure In addition the Commisshysion of the European Communities (EU) has selected ISO 28580 international standard as the basis of their rolling resistance rating system Use of ISO 28580 would allow international harshymonization of US and European test practices Should the ISO 28580 final draft international standard fail to be finalized in time for use in the system or be cancelled the SAE J1269 test is a reasonable alternative If the two ISO 28580 lab alignment tires fail to be made available either single-point rolling resistance test could use the ASTM F2493 16-inch standard reference test tire for continued lab alignment (a concept proven in Phase 1) and perhaps the ASTM E1136 14-inch SRTT as a second tire

The lab alignment procedure in ISO 2858014 which for passenger tires uses two dissimilar tires to calibrate a test lab to a master lab states that it will compensate for differences induced from tests conducted using different options under the test standard These options include the use of one of four measurement methods (force torque power or deceleration) textured or smooth drum surface correction of data to a 25C reference temperature and correction of data from tests conducted on a test drum of less than 20-m in diameter to a 20-m test drum The variabilshyity in test results induced by allowing the various test options as well as the effectiveness of the temperature and test drum correction equations is not currently known to the agency The ISO TC 31 technical committee15 responsible for the development of the 28580 rolling resistance standard has 20 participating countries of which the United States through ANSI16 is the secreshytariat and an additional 31 observing countries Therefore the ISO test standard strives to be functional with the various technical capabilities present in the 51 member and observer counshytries When such a test standard is applied for regulatory use in which compliance testing will be

14 Per ISO 28580 Section 1022 ldquoThe reference machine laboratory control tyre monitoring must occur at a maxishymum interval of one month Monitoring must include a minimum of 3 separate measurements sometime during this one month period The average of the 3 measurements made during a one month interval must be evaluated for drift from one monthly evaluation to anotherrsquo Per ISO 28580 Section 1055 ldquoThe alignment process must be repeated at least every second year and always after any significant machine change or any drift in candidate machine control tyre monitoring datardquo 15 ISO TC 31 Tyres rims and valves httpwwwisoorgisostandards_developmenttechnical_committeeslist_of_iso_technical_committeesiso_technica l_committeehtmcommid=47670 16 American National Standards Institute (ANSI) httpwwwisoorgisoaboutiso_membersiso_member_bodyhtmmember_id=2188

conducted and civil penalties for non-compliance may be levied17 it may be desirable to limit the application of the test method options so as to lessen the variability in the data submitted to agency This in turn may facilitate more accurate ratings and more effective compliance and enshyforcement activities

The first option to consider is the type of measurement methods allowed for testing The use of force torque and power methods are permitted by the domestic SAE standards with force and torque being the most common There is limited international use of the fourth method decelerashytion which is allowed under ISO test standards The agencyrsquos evaluation of the variability of the ISO 28580 test in Phase 1 could only be carried out on the available test equipment in the United States which were 1707-m test drums with force or torque measurement methods Due to the indirect nature of the power and deceleration measurement methods as opposed to the more dishyrect force or torque measurement methods and the agencyrsquos lack of access to test machines in the United States that use power or deceleration methods constraining the use of ISO 28580 to only force or torque methods of measurement for data submission to the consumer information system is advised

A second option allowed under ISO 28580 is the use of the specified smooth steel or optional textured (aka grit) material on the drum surface Each surface has its own benefits and tradeshyoffs when compared to the other which mainly revolve around maintenance of the test surfaces The smooth steel test drum specified in ISO 28580 requires frequent cleaning to remove tread rubber and oil build-up which can alter test results The roughness of the steel surface is to be maintained (presumably through grinding or polishing) at maximum centerline average height value of 63 μ-m The approximately 116th to 18th-inch thick textured surface material (similar to an 80-grit adhesive sand paper or 3M Safety-Walk tape) requires installation conditioning18 and eventual replacement However the textured surface inhibits a build-up of tread rubber and oil on the test drum surface The master lab for lab alignments under ISO 28580 will use a 20-m smooth steel roadwheel It is not known whether the proposed regional labs used for lab alignshyment will test on a smooth or a grit surface

All rolling resistance methods utilize a skim test to determine the non-tire losses of the test equipment which for the force and torque methods includes bearing and aerodynamics losses Skim measurements are conducted by loading the tire to a value just sufficient to maintain tire rotation at test speed without slippage The ISO 28580 standard states that a textured surface may be used to improve the skim test reading accuracy The rolling resistance of a tire is known to increase with increased surface roughness LaClair cited research by Luchini (1983) indicating a grit drum surface which is intended to more closely mimic a road surface is also more repeatshyable than a smooth steel surface However a grit surface can generate rolling resistance numbers 2-11 percent higher than a smooth surface[38][39] In NHTSA Phase 1 testing the rolling resisshytance of deep-lug tires exhibited a relatively linear behavior on grit surfaces over a range of test

17 Energy Independence Security Act(b) ENFORCEMENTmdashSection 32308 of title 49 United States Code is amendedmdash(c) SECTION 32304AmdashAny person who fails to comply with the national tire fuel efficiency informashytion program under section 32304A is liable to the United States Government for a civil penalty of not more than $50000 for each violationrsquorsquo 18 A conditioning procedure for a new textured (grit) surface is specified in SAE J2452 Issued JUN1999 Appendix B Surface Conditioning Procedure

loads but dropped off at the lighter loads on smooth steel drums This was attributed to slippage of the deep lug tires on the smooth19 surface Deep lug passenger vehicle tires (many of which are P-metric) are more common in the US market where textured drum surfaces are commonly used than in Europe where smooth drum surfaces are commonly used Additionally US test labs generally lack the capability to initially obtain and then maintain the surface roughness reshyquirements of the smooth steel test drum Conversely the European labs have little experience with the textured surface In consideration of this it is recommended that agency allow results from both surfaces for data submission However agency compliance testing should be conshyducted on the more accurate textured surface used domestically with lab alignment theoretically providing the 2-11 percent correction to a smooth surface

A third option allowed under ISO 28580 is the temperature correction of data to 25C from temshyperatures within the 20-30C range It is known that rolling resistance varies with temperature during on-vehicle operation According to LaClair ldquoThe variation in rolling resistance as a function of temperature is not linear However between 10 and 40C an increase of 1C corre-sponds to a reduction in rolling resistance of about 06 percent under normal road opera-tionrdquo[38] Assuming this relationship applies to laboratory testing as well the 5C (9 F) range allowed by ISO 28580 may translate into a maximum of 3 variation in rolling resistance Within the range of permissible laboratory ambient temperatures the standard specified a linear formula that corrects the Fr value of passenger tires by plusmn08 percent for each degree Celsius the temperature departs from 25C The correction is plotted in Figure 50 For passenger tires this correction can reach a maximum of 4 percent of the measured rolling resistance force Thereshyfore the correction appears to be reasonable in magnitude when compared to the stated road opshyeration response of rolling resistance to temperature

19 While the likely explanation the test lab was not equipped to measure tire slip during operation It is also signifishycant to note that the ldquobare steelrdquo wheel used in the NHTSA testing did not have a finish certified to average height of 63 μ-m

20 21 22 23 24 25 26 27 28 29 30 094

Ambiant Temperature (Celsius)

)Truck and bus (load index lt 121)

Passenger

Figure 50 Temperature Correction Factor - ISO 28580

A fourth option allowed under ISO 28580 is the correction of data to 20 meter drums commonly used in Europe from smaller test drums such as the 1707-m (6723-in) test drums commonly used in the United States Since no 20-meter drums were available for testing in the United States the variation in test results resulting from use of this formula have not been verified by the agency Figure 51 shows the equation in ISO 28580 used to correct Fr measured on a 1707shym drum to a 20-meter drum equivalent over a range of tire radii from 03 m to 05 m The corshyrection factor varies from 098 to 097 over this range or 2 to 3 percent of measured rolling force The correction equation is based on a theoretical concept that was not validated by the agency with different tire designs and sizes This again may introduce variability in the data reshyported to the system At a minimum reporting of results in terms of a single drum diameter will be necessary to prevent rating compliance disputes

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Correction Factor from 1707 m to 20 m drum diameter

Figure 51 Drum Diameter Correction Factor - ISO 28580

(D) A national tire maintenance consumer education program including information on tire inflation pressure alignment rotation and tread wear to maximize fuel efficiency safety and durability of replacement tires

The agencyrsquos wwwSafercargov website contains information and recommendations on tire inshyflation pressure alignment rotation and treadwear The test results from Phase 2 allow estimates of the effects of tire rolling resistance levels on fuel efficiency safety and the durability of tread of light vehicle replacement tires The results also attempt to quantify the effects of tire underinshyflation on vehicle fuel economy These results could be cited in consumer information

60 ROLLING RESISTANCE (FR) VERSUS ROLLING RESISTANCE COEFICIENT CR)

An important facet of the rating system is data reporting The two candidates for reporting of the data under the draft ISO 28580 standard are the rolling resistance (Fr) and the rolling resistance coefficient (Cr) The ISO 28580 standard defines rolling resistance as the ldquoLoss of energy (or energy consumed) per unit of distance travelledrdquo The standard defines rolling resistance coeffishycient (Cr) as the ldquoRatio of the rolling resistance in newtons to the load on the tire in knewtons This quantity is dimensionlessrdquo [40]

61 Theory of Fr and Cr

Schuring and Futamura define the units of rolling resistance as watt-seconds per meter or joules per meter (Jm) which is equivalent to newton meters per meter (N-mm)[41] The meter per meter (mm) is sometimes cancelled out in this notation to provide Fr in terms of newtons (N) alone However Schuring and Futamura emphasize that while the unit Jm is dimensionally equivalent to the newton (N) rolling resistance is not a force but rather an energy loss per disshytance traveled which is a scalar with no direction (ie not a vector)[41][42] Therefore ISO 28580 and ISO 18164 note that ldquoThe SI unit conventionally used for the rolling resistance is the newton metre per metre (N mm) This is equivalent to a drag force in newtons (N)rdquo[43] With the exception of SAE J1269 (circa 1979)20 the three most recent standards J2452 (circa 1999) ISO 18164 (circa 2005)21 and the draft ISO 28580 (expected 2009) have adopted language deshyfining rolling resistance as the energy a tire consumes per unit distance (See Definitions section of this report)

In ISO 28580 a laboratory rolling resistance test machine may use the force torque power or deceleration method to calculate the rolling resistance at interface of the tire and drum Subtracshytion of skim values and corrections are conducted with the data in the Fr format then the rolling resistance coefficient (Cr) is determined by dividing the Fr by the specified test load on the tire The concept of rolling resistance coefficient (Cr) stems from the fact that ignoring vehicle inshyputs the equilibrium (ie fully warmed up) rolling resistance of a new radial tire varies primarshyily with applied load inflation pressure and speed Investigations such as those by Clark et al during the 1970s indicated that the equilibrium tire rolling resistance of radial passenger tires was not linear with pressure or speed but did appear linear with load In the 1979 handbook preshypared for the US Department of Transportation Clark and Dodge explain the concept and apshyplication of the rolling resistance coefficient[44]

ldquoIn all four of these sets of data (two bias and two radial22 tire models) the linear relashytionship between load and rolling resistance is very close and further to a very close apshyproximation the rolling resistance vanishes at zero load with a straight line drawn through the data points nearly intersecting the origin of rolling resistance and load hellip

20 SAE J1269 was originally issued in 1979 reaffirmed in 2000 and revised and reissued in 2006 21 ISO 18164 was issued in 2005 but states that it is a compilation of three older individual standards (ISO 87671992 ISO 99481992 and ISO 133271998) that have since been withdrawn 22 Goodyear GR 78-14 and Uniroyal HR78-15

The linear nature of the equilibrium rolling resistance as a function of load is apparently fortuitous but is well known and has led to the common and very useful concept of the coefficient of rolling resistance which is defined as the rolling resistance divided by the load carriedrdquo

In their paper the authors continue on to explain how the rolling resistance coefficient can be used to evaluate different tires for a known vehicle[45]

ldquoThe coefficient of rolling resistance is a convenient concept since it allows one to comshypare various tires for use on the same vehicle The load carried by a tire will be the same on a given vehicle in a given tire position so a comparison of the rolling resistance coefshyficients will show which tire is the most efficient for a given application On the other hand tests of tire rolling resistance are usually carried out at the tire rated load or at some relatively large fraction of it such as 80 percent of tire rated load Direct presentation of the rolling resistance under these conditions is dependent on the load carried by the tire which of course varies for different tire sizes Hence the concept of the coefficient is a generalizing and extremely useful one for both the presentation and interpretation of datardquo

Therefore the concept of rolling resistance coefficient (Cr) would appear advantageous when calculating the expected rolling resistance of a tire or of tires of different load ranges or sizes for a ldquogiven applicationrdquo (ie for a given vehicle with known wheel corner loads) The coeffishycient Cr transforms the ldquoenergy per unit distancerdquo measure of Fr into terms of ldquoenergy per unit distance and unit loadrdquo on the tire As stated earlier no simple relationship exists between rollshying resistance and pressure or speed that would allow the calculation of similar coefficients for these two inputs

To determine the sensitivity of a tirersquos rolling resistance to load and pressure the first rolling reshysistance test standard SAE J1269 (1979) evaluated tire rolling resistance over a range of three pressures and two loads at 80 kmh (50 mph) (Figure 52) For passenger tires the two test loads are 50 and 90 percent23 of the maximum load limit of the tire The combination of pressure and load conditions result in four discrete test points (TP 1 to TP 4) Skim loads are subtracted from each test point and the data is corrected while still in terms of Fr If desired the standard specishyfies an option to fit a least-squares regression model to the data which uses separate equations for passenger light truck and highway truck and bus tires The linear regression equation for passenger car tires is

23 90 percent of maximum rated tire load is a logical upper limit for test load since FMVSS 571110 requires that the vehicle normal load on a tire not exceed 94 percent of the rated load of the tire at the vehicle manufacturerrsquos recshyommended cold inflation pressure of the tire For passenger tires installed on MPV truck bus or trailers the allowshyable rated load of the tire is reduced by 10 percent and the normal load must still not exceed the 94 percent of the de-rated load

FR = FZ(A0+A1FZ+A2p) FZ = Tire load (N [lbf])

p = Equilibrium inflation pressure (kPa [psi]) A0 A1 A2 = Coefficients

Equation 4 SAE J1269 Linear Regression Equation for Passenger Car Tires

Pr+70 kPa

Pr -50 kPa capped

Test Speed of 80 kmh [50 mph] Pressure

Pr -30 kPa

40 50 60 70 90

Figure 52 SAE J1269 Recommended Test - Evaluates Response of Rolling Resistance Force Over a Range of Three Pressures and Two Loads

After determining the coefficients of the equation in J1269 a predicted rolling resistance can be calculated at any load and pressure24 In the original SAE J1269 the Cr is determined by dividshying the Fr by the corresponding test load on the tire Since Cr is assumed to be a constant any Fr whether measured or predicted by the regression equation can be used in the calculation The latest version of SAE J1269 (2006) specifies a Standard Reference Condition (SRC) consisting of a single load and pressure from which Equation 4 can be used to calculate a standard Fr and Cr This latest version of the standard still recommends use of the multi-point test but states that the test may be conducted at the single-point SRC conditions ldquowhich may be used for the pur-pose of high volume comparisonsrdquo[46] However no version of J1269 states how Cr whether determined from multi or single-point methods is to be used

ISO 18164 (1992-1998)25 specifies a rolling resistance test with a single load and single inflation condition which can be run at either a single speed or three speeds Annex B of the standard specifies optional test conditions for determining the speed andor load and inflation sensitivity of a tire The standard states[43]

24 SAE J1269 (SEP 2000 Sept) p 10 states ldquoThe resulting regression equation may be used to calculate values for rolling resistance at loads and pressures other than those tested but extrapolation far beyond the range of the test matrix particularly for the region of high load and low pressure is not advisedrdquo 25 ISO 18164 was issued in 2005 but states that it is a compilation of three older individual standards (ISO 87671992 ISO 99481992 and ISO 133271998) which have since been withdrawn

ldquoThe rolling resistance of a tyre will vary with speed load and inflation pressure as well as other factors Depending on the circumstances of particular tyre applications it can be useful to determine the effect of these tyre-related parameters for the individual tyre to be tested If such information is desired the options indicated in (Annex) B2 and B3 are recommendedrdquo

In Annex B2 of ISO 18164 the speed sensitivity of passenger tires is evaluated at 50 kmh 90 kmh and 120 kmh in sequence In Annex B3 the load and inflation sensitivity of passenger tires are evaluated at two loads 50 and 90 percent of maximum load and two pressures +70 kPa and -30 kPa from the single-point pressure (Figure 53) Like the preceding SAE J1269 ISO 18164 subtracts skim loads and corrects the data in terms of Fr Unlike J1269 18164 does not contain an option in Annex B to fit a regression equation to data from multiple loads and presshysures If using the multi-point test conditions a Cr must be determined from dividing a measured Fr by its corresponding test load Again since Cr is assumed to be a constant any measured Fr can be used in the calculation The ISO 18164 standard also does not state how Cr is to be used

Pr+70 kPa

Test Speeds of 50 kmh 90 kmh and 120 kmhPressure

TP 1 TP 3

TP 2Pr -30 kPa

Figure 53 ISO 18164 Annex B - Response of Rolling Resistance Force (Fr) Over a Range of Three Speeds Two Pressures and Two Loads

The later SAE J2452 (circa 1999) goes farther in continuously measuring rolling resistance over a stepwise speed coastdown from 115 to 15 kmh (71 to 9 mph) As with SAE J1269 and ISO 18164 J2454 recommends testing at a matrix of loads and pressures[47]

ldquoIn order to obtain a complete quantification of tire rolling resistance as a function of load inflation pressure and speed the loadpressure matrices specified in 721 should be

used However if needed the stepwise coastdown can be performed for a single loadpressure conditionrdquo

The first data reduction process uses a mathematical model to describe a tirersquos rolling resistance as a function of load inflation pressure and speed Interestingly while the J2452 test includes a definition of Cr it does not calculate Cr in the standard Instead the standard calculates a mean equivalent rolling force (MERF) which is the average rolling resistance of a tire at a loadinflation condition over a driving cycle with a specified speed-time profile J2452 also alshylows calculation of a standard mean equivalent rolling force (SMERF) at a single-point reference condition (a single load pressure and speed)

To save time and expense the draft ISO 28580 rolling resistance standard calculates rolling reshysistance Fr at single load pressure and speed (Figure 54) Subtraction of skim values and correcshytions are conducted with the data in the Fr format then the rolling resistance coefficient (Cr) is determined by dividing the Fr by the nominal test load on the tire (Equation 5)

Cr = FrLm

Cr = Rolling resistance coefficient (dimensionless) Fr = Rolling resistance in newtons Lm = Test load in knewtons

Equation 5 ISO 28580 Rolling Resistance Coefficient

Test Speed of 80 kmh (50 mph)Pressure

210 kPa capped

Figure 54 ISO 28580 Test Conditions for Standard Load Passenger Tires

As with the three other test standards there is no mention in ISO 28580 of how Cr is to be used However the test standard states in its scope[40]

ldquoMeasurement of tyres using this method enables comparisons to be made between the rolling resistance of new test tyres when they are free-rolling straight ahead in a position perpendicular to the drum outer surface and in steady-state conditionsrdquo

The most straightforward interpretation is that the rolling resistance coefficient in ISO 28580 is intended to normalize rolling resistance by test load to allow a relative comparison of the energy consumption of tires of all sizes and load ranges However the previous discussion has illusshytrated how the Cr coefficients from multi-point (multi-load) rolling resistance are used to calcushylate the rolling resistance of a tire at a known wheel load (vehicle load divided by four) usually for the purpose of evaluating a tire or tires for a given vehicle This calls into question whether the Cr calculated from a test at single load can also be used for such purposes

611 Using Cr from a Single-Load Test to Predict Rolling Resistance at Any Load

There are a number of assumptions that must be fulfilled to be able to predict the response of a tirersquos rolling resistance over a range of loads from measurement of rolling resistance at a single load First since a single-point in space can have an infinite number of lines pass through it a second point must be defined in order to determine the sensitivity of a tirersquos rolling resistance to load For the purposes of a single-point Cr this second point is defined as the origin (Figure 55) Since this function is a straight line defined by two points the actual response of rolling resisshytance to load changes should be fairly linear or errors will be induced Second to use Cr as a scashylar to vehicle load the rolling resistance coefficient should be constant (ie a flat line) over the range of practical tire loads or errors will be induced (Figure 56)

Theoretical Fr

Tire B

Tire A

Test Speed of 80 kmh (50 mph) Capped Pressure of 210 kPa (30 psi)

Rolling Resistance (N)

Figure 55 Theoretical Single-Load Rolling Resistance (Fr)

Tire A

Theoretical Cr

Tire B

Rolling Resistance Coefficient

(Dimensionless)

Figure 56 Theoretical Single-Load Rolling Resistance Coefficient (Cr)

In Phase 1 of this project the agency measured the rolling resistance of 16 passenger tire models in a number of single and multi-point tests Figure 57 displays rolling resistance data for the tires over a range of loads in the various tests (all points were collected at the identical pressure and speed) Note that the two points are connected with straight lines to emphasize that the Fr is not a linear function passing through the intercept It is likely that the actual Fr values do pass through the intercept (ie there is zero rolling resistance at zero load) but that the function is actually non-linear as is hypothesized in the SAE J1269 (multi-point) regression shown in Equation 4 Figure 58 displays rolling resistance (Cr) data for same tires over the range of loads Itrsquos imporshytant to note that the Cr values in Figure 58 at different loads are not constant sometimes increasshying and sometimes decreasing with load depending on the given tire model In other words Cr does not appear to be a constant coefficient which is why the multi-point tests evaluate rolling resistance over a range of loads and use non-linear regressions to predict a tirersquos response to load

Type B10 B11 B12 B13 B14 B15 D10 G10 G11 G8 G9 M13 M14 P5 R4 U3

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

Figure 57 Rolling Resistance of 16 Passenger Tires Versus Load at Constant Pressure (Average of 8 Values)

600 800 1000 1200 1400 1600

Figure 58 Rolling Resistance Coefficient of 16 Passenger Tires Versus Load at Constant Pressure (Average of 8 Values)

Beyond the inconsistencies with Cr there exist practical problems in that very few vehicles are operated at the GAWRGVWR listed on the placard and few tire dealers have vehicle scales that allow determination of actual vehicle weight Without a know corner load for a tire the Cr canshynot be used to calculate a rolling resistance for a given tire model A standard estimate of pershycentage of a vehiclersquos GVWR to use Cr to estimate Fr would likely not be more predictive than the Fr measured at 80 percent of maximum tire load rating Also there comes additional diffishyculty in predicting the rolling resistance of a tire for a given vehicle from a single-pressure test The allowable placard inflation pressures for standard load passenger car tires range from 180 kPa (26 psi) to 240kPa (35 psi) and up to 280 kPa (41 psi) for extra load tires No similar coeffishycient is available from ISO 2858026 to correct the expected Fr from the 210 kPa (30 psi) standard load (250 kPa [36 psi] extra load) test pressure in the standard to the actual placard operating pressure of the vehicle which can differ by axle Therefore the idea of calculating rolling resisshytance for a specific vehicle is not usually possible with Cr unless its tires operate at the ISO

26 Note that the coefficient in the SAE J1269 test for passenger tires is A2p rolling resistance varies by the inverse of the inflation pressure

28580 test pressure or a multi-point rolling resistance test is used to generate a regression equashytion from tests at multiple pressures

62 Discussion

It has been asserted that Cr would be more useful than Fr as a basis of rating tires for consumers who are looking to replace tires on their vehicle with tires of the same size but different maxishymum load ratings The FMVSS No 139 allows tire maximum load ratings to be determined from one of six international organizations27 or to be specified to the agency by an individual manushyfacturer For example the agencyrsquos Phase 1 research used a large number of tire models of the most popular P-metric replacement tire size in 2007 which was P22560R16 The standard load P22560R16 Goodyear Integrity tire (type G12) which was OE on the test vehicle has a load index of 97 that allows it to carry a maximum of 730 kg (1609 lbs) at maximum pressure The metric designated 22560R16 Goodyear Integrity tire (type G8) has a load index of 98 allowing it to carry 750 kg (1653 lbs) or 20 kg (44 lbs) more at maximum pressure Per ISO 28580 both tires are tested at 80 percent of maximum load resulting in the G8 tire being tested at 16 kg (35 lbf) more load in the rolling resistance test In this test the average rolling resistance of the P22560R16 Integrity tire was 947 lbs and the 22560R16 was 983 lbs a 036 lbf (+4) differshyence

To adjust for the different test loads the rolling resistance coefficient (Cr) is calculated Acshycounting for significant digits the Cr of the P22560R16 is 947 lbf 1287 lbf = 00074 lbflbf and the Cr of the 22560R16 is 983 lbf 1322 lbf = 00074 lbflbf Therefore since the Cr values were identical the 4 percent difference between the two Integrity tires likely resulted from the different test loads not the tires themselves If the tires were rated strictly on the ISO 28580 Fr magnitudes the P22560R16 tire has lower rolling resistance than the 22560R16 tire This issue has implications in that for many sizes of tires the metric designated tires (usually of European or Asian manufacture) have a marginally higher load index than the P-metric tires28 As a result the metric tires would be tested at higher loads than P-metric tires of the same size and yield slightly higher rolling resistance However this does not appear to be a penalty in that a tire of a given size that is rated with a higher load index for instance a 98 load index rather than a 97 could be operated at higher loads on heavier vehicles and actually generate more rolling resisshytance

27 The tire load rating shall be that specified either in a submission made by an individual manufacturer pursuant to S4 or in one of the publications described in S4 for its size designation type and each appropriate inflation pressure If the maximum load rating for a particular tire size is shown in more than one of the publications described in S4 each tire of that size designation shall have a maximum load rating that is not less than the published maximum load rating or if there are differing maximum load ratings for the same tire size designation not less then the lowest pubshylished maximum load rating S4 (1) The Tire and Rim Association (2) The European Tyre and Rim Technical Orshyganization (3) Japan Automobile Tire Manufacturersrsquo Association Inc (4) Tyre amp Rim Association of Australia (5) Associacao Latino Americana de Pneus e Aros (Brazil) (6) South African Bureau of Standards (Source FMVSS No 571139 28 In a survey of 69 tire sizes sold by the Tire Rack in both P-metric and Euro-metric sizes 12 percent had equal load designations 85 percent had load designations from 1 to 6 load index numbers higher (average of 15) for the Euro-metric size and 1 size had a higher load index designation for the P-metric tire

Nonetheless normalizing all tires to their test load with Cr in order to provide a relative measure of their rolling resistance may be useful if the normalization is indeed consistent across all tire sizes It is therefore necessary to think outside the context of selecting tires for a known vehicle and consider the rating system as a whole Neither Fr nor Cr have been used before to rate a large population of tires in a common rating system It is absolutely factual to state that for a given veshyhicle which has a single nominal tire load Fr and Cr will produce identical rankings of tires of the same size and load index However the proposed tire fuel efficiency rating system must rate all tires in the system independently of specific vehicles and recognize that a given tire model may be operated at many different loads In 2009 Lambillotte estimated that a rolling resistance rating system in the United States may cover greater than 20000 individual passenger tire stock-keeping units (ie unique tire brandmodelsizepattern etc designations)[48] Therefore it is important to consider the implications of using Cr to categorize a wide range of tires in a rating system When Cr is applied over a large range of tire sizes it tends to produce lower relative valshyues for larger tires than for smaller tires despite the fact that the larger tires will very likely use more energy This in turn skews the grades of tires when compared in a common system Schurshying and Futamura reported this trend in 1980rsquos era tires (13-15 inch tires sizes)[49]

ldquoIf a family of tires of different sizes would be tested for rolling loss at a maximum load (prescribed by the Tire and Rim Association) or at a fixed fraction of maximum load as well as at a constant pressure and constant speed and if rolling loss would be directly proportional to maximum load (or a fraction thereof) then by definition the rolling loss coefficient derived from these test would be independent of size This however is not the rule Rolling loss does increase not quite in proportion with increasing maximum load (or fractions of it) hence the rolling-loss coefficient of larger tires is mostly smaller than those of smaller tires hellip The reason for the slight decline in the rolling-loss coefficient with tire size is not clear We may speculate that the load formula (a rather complex emshypirical relation between permissible tire load pressure and tire dimensions developed and continuously amended over the decades by the Tire and Rim Association) had been adjusted such that larger tires experience slightly lower strains than smaller tiresrdquo

What Schuring and Futamura observed in 13- to 15-inch diameter tire sizes and has since been magnified as tires reach 30-inch diameters and beyond is a result of the load term (Lm) in the denominator of the Cr equation (Cr = FrLm) This is where the non-linear formulas that detershymine the maximum load ratings for tires have a large effect For instance Equation 6 in Appendix 1 is the maximum load formula used by the Tire and Rim Association Inc Note the multiple coefficients raised to powers as well as the three different values for the K coefficient depending on the aspect ratio of the tire It is obvious that the Tire and Rim Association load formula is going to provide three different non-linear curves for maximum load across the range of passenger tire sizes to be rated in the tire fuel economy system Dividing the rolling resistance force (Fr) by this non-linear and discontinuous function will result in a non-linear and disconshytinuous set of values for Cr Additionally certain P-metric tires of aspect ratios 30-45 have maximum loads that do not follow the TampRA formulas and were instead set equal to ISO loads in order to harmonize internationally Worse yet a sizable portion of tires sold in the United States are metric tires (tire sizes lacking a ldquoPrdquo at the beginning) and are rated by a different set of equations under the ISO standards The Tire Rack has an excellent description of the two sysshytems in laymanrsquos terms[50]

ldquoP-metric sized tires are the ones with the P at the beginning of the tire size (such as P22560R16 listed above) They were introduced in the United States in the late 70s and are installed on vehicles primarily used to carry passengers including cars station wagshyons sport utility vehicles and even light duty pickup trucks Their load capacity is based on an engineering formula which takes into account their physical size (the volume of space for air inside the tire) and the amount of air pressure (how tightly the air molecules are compressed) Since all P-metric sizes are all based on the formula for load vehicle manufacturers can design their new vehicles (weights and wheel well dimensions) around either existing or new tire sizes

Metric or Euro metric sized tires are the ones without the P at the beginning (such as 185R14 or the 22560R16 listed above) Using metric dimensions to reflect a tires width actually began in Europe in the late 60s However since Euro metric sizes have been added over time based on the load and dimensional requirements of new vehicles the tire manufacturers designed many new tire sizes and load capacities around the needs of new vehicles Not quite as uniform as creating sizes using a formula but they got the job donerdquo

Therefore the idea of generating a linear dimensionless coefficient in Cr by dividing Fr by 80 percent of maximum rated tire load puts either the three different TampRA non-linear load formushylas or the ad hoc European system of load capacities into the denominator of the equation While the effects on selecting tires for a given vehicle are almost certainly negligible the effects on ratshying all tires of all sizes in a common system with Cr may be significant For instance Figure 59 shows the Fr calculated for values of passenger tire rolling resistance reported by the Rubber Manufacturers Association (RMA) to the California Energy Commission [51] versus the load index reported for the tires Excluding what appear to be outliers the values range from 5 pounds to approximately 22 pounds Figure 60 shows the values of Cr for the same tires Excluding the same tires that appear to be outliers the values range from 6 to approximately 14 Two important conclusions can be seen in this data

1 The range of Fr values from lowest to highest is ~13 times the mean value for all tires while the range for Cr values is only ~08 times the mean value This means that Fr will have a greater ability to discriminate tires across the entire range of passenger tires (As previously noted at a given load index the values for Fr and Cr are related by a constant therefore the ability to discriminate tires at the same load index is identical)

2 The average value for Fr increases with load index meaning the amount of energy loss (vehicle fuel consumption) is increasing as tire load indexes increase However the avshyerage value for Cr decreases as tire load index increases In fact dividing by load does not produce a ldquocorrectedrdquo value for a tire that is independent of load but rather a value that is inverse to load

75 85 95 105 115 125

Load Index

Figure 59 Rolling Resistance Force (SAE J1269 Single-Point Pounds) Versus Load Index for a Broad Range of Passenger Tires

75 85 95 105 115 125

Load Index

Figure 60 Rolling Resistance Coefficient (SAE J1269) Versus Load Index for a Broad Range of Passenger Tires

This is where the goals of the fuel efficiency rating system must be considered First and foreshymost the system should be intuitive to consumers Consumers will use the system to purchase tires for their current vehicle as well as for subsequent vehicles thus building up a contextual understanding of the ratings over time Also consumers may have multiple vehicles in their household or commercial fleet for which they purchase tires A system based on the rolling resisshytance of each tire is directly relatable to fuel economy calculations and does not skew larshygerhigher load tires into better ratings such as a system using Cr as a basis Regardless of whether any two tire sizes in the system actually fit on the same vehicle consumers could be confused by a fuel efficiency system that gives equal or better ratings to larger tires that consume more fuel than to smaller tires that consume less fuel

For instance in rating light vehicle fuel economy the estimated fuel mileage given to consumers is not divided by the rated payload capacity of the vehicle Vehicle fuel economy ratings are inshystead an estimate of fuel efficiency of all vehicles in the system under the same set of driving conditions Given vehicle fuel economy the consumer may then weigh the fuel efficiency of the vehicle against any consideration such as payload capacity top speed number of occupant seats etc Consumers who require certain cargo or towing capacities are no more able to choose a smaller more fuel efficient vehicle any more than a consumer with a large truck can choose a small low-rolling resistance tire However the estimated fuel economy of the light vehicles is reported on the same basis regardless of vehicle type Consumers should understand that heaviest passenger vehicles tend to get the poorest fuel economy in part because the large tires operating under the heavy loads of those vehicles consume more energy

Another model is the UTQGS system The UTQGS treadwear rating is intuitive to consumers in that tires with higher grades will under the same conditions be expected to last longer than tires with lower grades This property is reported independent of any other tire property Take for inshystance the speed category (maximum speed rating) of the tire High-performance ZR V W and Y rated tires which have much lower average treadwear grades than all season S T U and H rated tires do not use a different reference tire for treadwear grading Nor is the treadwear rated divided by the speed category Instead all tires in the system are referenced on the same scale even though an ultra-high performance summer tire is likely not available in the OE sizes of a minivan or economy car The same is true of the traction and temperature resistance ratings We believer consumers expect high performance tires to have higher traction and temperature resisshytance ratings than S-rated tires and would find a relative system one in which a W-rated tire that is expected to wear out in fewer miles is given a higher rating than an S-rated tire that is exshypected to last longer to be confusing

An additional argument has been put forth that by providing consumers with fuel economy recshyommendations for small and large tires on the same scale (use of Fr) rather than normalizing everything to load capacity (use of Cr) the system may encourage consumers to choose smaller tires with insufficient load carrying capacity for their vehicles thus creating a safety hazard This rationale is flawed for many reasons First consumers have had a strong economic benefit to purchase under-capacity tires for many decades namely initial purchase price The smaller tires in a tire line normally cost less and purchasing under-capacity tires would be an immediate ecoshynomic benefit at the time of sale This is contrasted with a future benefit of 6 to 12 gallons in anshynual fuel savings from purchasing tires with 10 percent lower rolling resistance than their current

tires[52] The issue of lower-cost small tires has not manifested itself as a safety problem due mainly to the fact that consumers lack the equipment to mount their own tires and that tire inshystallers will not assume the legal liability for installing tires with insufficient load carrying capacshyity

Finally there comes the matter of calculating fuel economy from the output of the rolling resisshytance test The calculated rolling resistance can be used to estimate a tirersquos power consumption or when set equivalent to a drag force on a vehicle to calculate its impact on vehicle fuel conshysumption The various analyses range from simple to highly complex fuel economy models In an example of a simplified approach Pillai defined tire energy loss per hour ldquoE(R)rdquo equal to the rolling resistance x distance traveled per hour[53] For example at the ISO 28580 test speed of 80kmh a tire with a Fr of 50 N (50 N-mm) consumes 11 kW of power per hour (50 N-mm 80 kmh (1000 m 1 km) (1 h 3600 s) = 1111 N-ms = 11 kW) For a tire with an Fr of 40 N it consumes 08 kW of power per hour at 80 kmh Therefore rolling resistance (Fr) is a ratio of the energy consumed per unit distance which when expressed at a given speed can differentishyate tires on the basis of expected power consumption

The tire energy consumption or vehicle fuel economy approaches require rolling resistance in terms of force for the calculations Tires of vastly different drag forces can have identical rolling resistance coefficients Therefore when the data is reported in terms of Cr the coefficient must be used to calculate an Fr at a known tire load or the initial step of converting Fr to Cr at 80 pershycent of maximum tire load must be reversed In other words data reported in terms of Fr is dishyrectly relatable to vehicle fuel economy Whereas data reported in Cr must be transformed back to Fr to allow vehicle fuel economy calculations Given the nature of Cr to skew tires that conshysume more fuel into better relative ratings the question persists as to the value of the extra step of computing a single-point coefficient rather than reporting the data in terms of Fr

Appendix 1 Tire and Rim Association Inc - Maximum Load Formula for ldquoPrdquo Type Tires

Maximum Load ldquoLrdquo (kg) = (K) x (P050) x (Sd139) x (Dr + Sd) [54]

Variable 30 Series Through 35 Series 40 Series Through 45 Series 50 Series Through 80 Series K 500 x 10-5 567 x 10-5 667 x 10-5

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

S70 S85 Nominal Tire Section (mm) H Section Height (mm) Dr Rim Diameter Code (mm) P Inflation Pressure (kPa) 240 kPa for Standard Load Tires or 280 kPa for Extra Load Tires

Equation 6 TampRA Load Formula for ldquoPrdquo Type Tires (SI Units)

Appendix 2 Detailed Test Matrix Tire

Model 1st Task 2nd Task EPA 5-Cycle Vehicle Fuel

Economy Indoor Tread-wear

Outdoor Dry Traction

Outdoor Tread-wear

Outdoor Wet Traction

Grand Total

Transportation Research Center Inc

Smithers Scishyentific Sershyvices Inc

NHTSA San Anshygelo Test Facility

NHTSA San Angelo Test Facility

B10 J2452 3 1 1 5 J1269 - Multishypoint

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

J1269 - Single-point

J1269 - Multishypoint

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

D10 J2452 3 1 1 5 J1269 - Multishypoint

3 1 1 5

G10 J2452 3 1 1 5 J1269 - Multishypoint

3 1 1 5

G12 ISO 28580 ISO 18164 2 2 EPA 2008 TRC EPA 2008 TRC 2 2

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

1 1 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

R4 J2452 3 1 1 5 J1269 - Multishypoint

3 1 1 5

U3 J2452 3 1 4 J1269 - Multishypoint

1 1 1 3

ISO 28580 2 1 3 Grand Total

52 48 32 20 32 184

Appendix 3 Examples of Data Acquired From Indoor Treadwear Test

Appendix 4 Raw Dry Traction Testing Results - Asphalt Barcode Candidate

Tire Number

Test Number

Brand Tire Line Tire Size Average Slide

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3141 080211 0830063 BridgestonePOTENZA RE92 P22560R16 593 30 648 564 953 17 979 929

3498 080113 0830065 Goodyear INTEGRITY P22560R17 651 10 662 634 970 10 985 960 3504 080118 0830066 Goodyear INTEGRITY P22560R17 643 12 656 628 979 25 1018 950 3455 080119 0830068 Goodyear INTEGRITY P20575R14 745 14 769 731 988 28 1023 953 3449 080123 0830069 Goodyear INTEGRITY P20575R14 738 13 752 719 977 16 991 955 3473 080126 0830070 Goodyear INTEGRITY P20575R15 727 10 738 711 976 16 1002 956 3479 080129 0830071 Goodyear INTEGRITY P20575R15 754 14 778 739 994 32 1051 963

3627 080131 0830074 Michelin PILOT HX MXM4 22560R16 527 11 541 516 993 11 1007 982

3727 080145 0830076 Uniroyal

TIGER PAW ASTM F 2493 SRTT P22560R16 670 19 688 647 994 31 1038 963

3733 080146 0830077 Uniroyal

3161 080151 0830079 BridgestonePOTENZA RE750 22560R16 551 06 561 542 1027 18 1053 999

3702 080161 0830081 Pirelli P6 FOUR SEASONS 22560R16 682 30 720 643 1043 32 1080 1003

3211 080166 0830085 Bridgestone TURANZA LS-V P22560R16 737 31 784 706 1017 14 1037 993 3217 080168 0830086 Bridgestone TURANZA LS-V P22560R16 779 12 794 762 1014 28 1032 959

3325 080171 0830087 Cooper LIFELINER TOURING SLE 22560R16 621 22 659 603 942 26 981 903

Barcode Candidate Tire

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3344 080175 0830090 No brand name WINTERFORCE 22560R16 662 17 687 641 908 31 955 872

3369 080182 0830092 Dunlop SP 4000 DSSST C P22560R17 667 24 705 634 914 23 947 887

3111 080187 0830096 Bridgestone

BLIZZAK REV01 STUDLESS 22560R16 777 28 802 724 941 12 954 924

3117 080190 0830097 Bridgestone

3419 080104 0830098 Goodyear INTEGRITY 22560R16 666 11 677 646 956 31 1018 922 3425 080108 0830099 Goodyear INTEGRITY 22560R16 654 18 681 636 932 28 978 907 3683 080203 0830101 Futura TOURING HR P22560R16 578 18 603 553 952 27 982 918 3677 080207 0830102 Futura TOURING HR P22560R16 561 09 574 550 960 18 982 930 3192 080197 0830103 Bridgestone TURANZA LS-T P22560R16 563 16 584 545 952 24 982 928 3186 080199 0830104 Bridgestone TURANZA LS-T P22560R16 589 09 600 577 945 31 994 914

Appendix 5 Raw Dry Traction Testing Results - Concrete Barcode Candidate

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

3186 080199 0830104 Bridgestone TURANZA LS-T P22560R16 761 29 777 703 943 23 968 914 3192 080197 0830103 Bridgestone TURANZA LS-T P22560R16 768 25 786 718 896 48 974 851 3211 080166 0830085 Bridgestone TURANZA LS-V P22560R16 851 16 877 833 1061 38 1128 1012 3217 080168 0830086 Bridgestone TURANZA LS-V P22560R16 849 22 878 812 1091 24 1132 1056

3419 080104 0830098 Goodyear INTEGRITY 22560R16 761 22 789 739 948 27 981 906 3425 080108 0830099 Goodyear INTEGRITY 22560R16 745 15 757 720 917 21 948 894 3449 080123 0830069 Goodyear INTEGRITY P20575R14 784 13 804 771 1011 41 1064 977

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3455 080119 0830068 Goodyear INTEGRITY P20575R14 793 20 815 766 1033 24 1060 1002 3473 080126 0830070 Goodyear INTEGRITY P20575R15 795 14 817 778 1029 17 1051 1002 3479 080129 0830071 Goodyear INTEGRITY P20575R15 773 12 796 760 1013 23 1041 971 3498 080113 0830065 Goodyear INTEGRITY P22560R17 760 10 772 745 1037 31 1085 1000 3504 080118 0830066 Goodyear INTEGRITY P22560R17 759 06 765 749 1045 16 1069 1022

3677 080207 0830102 Futura TOURING HR P22560R16 727 27 758 695 974 45 1017 888 3683 080203 0830101 Futura TOURING HR P22560R16 704 19 737 681 919 39 980 877

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Appendix 6 Raw Wet Traction Testing Results - Asphalt Barcode Candidate

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3626 080133 0830004 Michelin PILOT HX MXM4

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

3726 080144 0830014 Uniroyal TIGER PAW ASTM F 2493 SRTT

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

3503 080114 0830016 Goodyear INTEGRITY P22560R17 498 11 523 481 829 18 867 808 3497 080115 0830017 Goodyear INTEGRITY P22560R17 500 10 517 478 830 18 868 810 3424 080105 0830020 Goodyear INTEGRITY 22560R16 492 07 502 481 874 19 921 850 3418 080109 0830021 Goodyear INTEGRITY 22560R16 485 04 492 478 878 23 916 846 3166 080152 0830022 Bridgestone POTENZA

RE750 22560R16 588 07 599 576 959 30 1020 924

3160 080155 0830023 Bridgestone POTENZA RE750

22560R16 594 08 612 583 961 27 1010 925

3447 080121 0830026 Goodyear INTEGRITY P20575R14 543 10 557 528 821 30 866 790 3453 080124 0830027 Goodyear INTEGRITY P20575R14 551 11 565 529 823 25 867 788 3116 080191 0830028 Bridgestone BLIZZAK

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

3110 080192 0830029 Bridgestone BLIZZAK REV01 STUDLESS

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

3478 080125 0830034 Goodyear INTEGRITY P20575R15 552 11 580 540 835 29 868 761 3472 080130 0830035 Goodyear INTEGRITY P20575R15 549 07 566 537 835 33 876 774

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3707 080158 0830040 Pirelli P6 FOUR SEASONS

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

3318 080172 0830044 Cooper LIFELINER TOURING SLE

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

3185 080194 0830050 Bridgestone TURANZA LS-T P22560R16 568 13 581 540 916 27 958 859 3191 080200 0830051 Bridgestone TURANZA LS-T P22560R16 586 08 597 567 930 36 973 868 3218 080163 0830052 Bridgestone TURANZA LS-V P22560R16 595 12 612 565 950 32 1010 916 3212 080165 0830053 Bridgestone TURANZA LS-V P22560R16 582 13 600 552 938 21 971 905 3676 080206 0830056 Futura TOURING HR P22560R16 547 05 555 538 840 25 871 802 3682 080208 0830057 Futura TOURING HR P22560R16 538 04 545 532 843 34 886 800 3135 080210 0830060 Bridgestone POTENZA

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Appendix 7 Raw Wet Traction Testing Results - Concrete Barcode Candidate

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Appendix 8 UTQG Adjusted Wet Traction Testing Results Barcode Candidate

Tire Number

Test Number

Brand Tire Line Tire Size Raw Asphalt Average

Slide Coefficient

Raw Concrete Average

Slide Coefficient

UTQG UTQG Adjusted Adjusted Asphalt Concrete

Slide Coefficient

Labeled Traction Grade

Attained Traction Grade

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

3503 080114 0830016 Goodyear INTEGRITY P22560R17 0498 0366 047 037 A A 3497 080115 0830017 Goodyear INTEGRITY P22560R17 0500 0365 048 037 A A 3424 080105 0830020 Goodyear INTEGRITY 22560R16 0492 0354 047 035 A B 3418 080109 0830021 Goodyear INTEGRITY 22560R16 0485 0348 046 035 A B 3166 080152 0830022 Bridgestone POTENZA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

3447 080121 0830026 Goodyear INTEGRITY P20575R14 0543 0366 051 036 A A 3453 080124 0830027 Goodyear INTEGRITY P20575R14 0551 0362 051 036 A A 3116 080191 0830028 Bridgestone BLIZZAK

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 0525 0355 049 035 none B

3343 080180 0830033 No brand name

3478 080125 0830034 Goodyear INTEGRITY P20575R15 0552 0372 051 037 A A 3472 080130 0830035 Goodyear INTEGRITY P20575R15 0549 0362 050 036 A A 3707 080158 0830040 Pirelli P6 FOUR

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

Slide Slide Coefficient Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

3185 080194 0830050 Bridgestone TURANZA LS-T P22560R16 0568 0408 053 039 A A 3191 080200 0830051 Bridgestone TURANZA LS-T P22560R16 0586 0411 055 039 A AA 3218 080163 0830052 Bridgestone TURANZA LS-V P22560R16 0595 0429 057 041 AA AA 3212 080165 0830053 Bridgestone TURANZA LS-V P22560R16 0582 0415 055 040 AA AA 3676 080206 0830056 Futura TOURING HR P22560R16 0547 0414 053 040 A A 3682 080208 0830057 Futura TOURING HR P22560R16 0538 0405 052 039 A A 3135 080210 0830060 Bridgestone POTENZA

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Appendix 9 ASTM E501 Reference Tire Wet Traction Testing Results

Asphalt Concrete Average Slide Average Peak Average Slide Average Peak

Tire Number

Number

Tire Line

Tire Size Slide STDev Peak STDev Slide STDev Peak STDev

Candidate Test Numbers

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Appendix 10 ASTM E501 Reference Tire Dry Traction Testing Results

Number

Tire Line

Tire Size Slide STDev Peak STDev Slide STDev Peak STDev080081 0831062 ASTM E501 G78-15 675 14 699 661 818 08 832 806 080081 0831078 ASTM E501 G78-15 627 62 707 563 812 14 828 796 080081 0831094 ASTM E501 G78-15 617 22 661 599 763 37 817 709 080082 0831067 ASTM E501 G78-15 683 25 724 652 820 11 833 805 080082 0831083 ASTM E501 G78-15 640 29 682 591 815 06 823 808 080082 0831095 ASTM E501 G78-15 621 33 659 572 820 17 847 798 080083 0831072 ASTM E501 G78-15 668 24 696 642 804 12 821 787 080083 0831084 ASTM E501 G78-15 590 18 619 567 811 28 849 783 080083 0831100 ASTM E501 G78-15 592 08 607 586 781 30 832 743 080084 0831073 ASTM E501 G78-15 671 18 689 644 828 15 849 811 080084 0831089 ASTM E501 G78-15 631 40 672 579 790 20 812 765 080084 0831105 ASTM E501 G78-15 604 15 625 589 775 42 819 718

REFERENCES

1 Hall DE amp Moreland JC (2001) Fundamentals of Rolling Resistance Rubb Chem Technol 74 No 3 525

2 Rubber Manufacturers Association (2008) Statistics North American Marketplace Tire Shipments US and Canada Updated February 2008 Washington DC Rubber Manufacturers Association Available at wwwTireBusinesscom

3 United States Congress (2003) Making Appropriations for Agriculture Rural Development Food and Drug Administration and Related Agencies for the Fiscal Year Ending September 30 2004 and for Other Purposes November 25 2003 p 971 United Conference Report 108-401 to Accompany HR 2673 Washington DC United States Congress

4 National Research Council of the National Academies (2006) Tires and Passenger Vehicle Fuel Economy Special Report 286 Washington DC Transportation Research Board

5 LaClair T J Rolling Resistance p 476-477 in The Pneumatic Tire Gent AN amp Walter JD (Ed) (2006) DOT HS 810 561 Published under contract DTNH22-02-P-07210 Washington DC National Highway Traffic Safety Administration

6 LaClair p 477 7 Department of Energy (2009) Advanced Technologies and Energy Efficiency Where Does

the Energy Go Washington DC Department of Energy Available at Web site httpwwwfueleconomygovfegatvshtml

8 Duleep KG (2005) Tires Technology and Energy Consumption PowerPoint Presentation Energy Efficient Tyres Improving the On-Road Performance of Motor Vehicles 15-16 November 2005 International Energy Agency Paris France

9 National Research Council p 30 Washington DC Transportation Research Board 10 Reimpell J Stoll H amp Betzler J W (2001) Published in The Automotive Chassis

Engineering Principles 2nd Edition p 123 Reprinted by SAE International Warrendale PA Oxford UK Reed Elsevier PLC Group

11 LaClair p 501 12 National Research Council p 33 13 NHTSA (2006) Traffic Safety Facts 2005 A Compilation of Motor Vehicle Crash Data

from the Fatality Analysis Reporting System and the General Estimates System DOT HS 810 631 Washington DC National Highway Traffic Safety Administration httpwww-nrdnhtsadotgovPubsTSF2005PDF

14 LaClair p 500 15 United States Congress (2007) Energy Independence and Security Act of 2007 Section 111

Consumer Tire Information 16 Evans L R amp W H Waddell (1995) Kautsch Gummi Kunstst Vol 48 p 718 17 Wolff S (1982) Rubb Chem Technol Vol 55 p 967 18 Futamura S (1990) Rubb Chem Technol Vol 64 p 57 19 Futamura S (1990) Tire Science and Technology TSTCA Vol 18 p 2 20 CFR Title 40 sect86 Title 40--Protection of Environment Chapter I--Environmental Protection

Agency (Continued) Part 86--Control Of Emissions From New And In-Use Highway Vehicles And Engines Washington DC Code of Federal Regulations httpwwwaccessgpogovnaracfrwaisidx_0740cfr86_07html

21 EPA (2009) Many Factors Affect MPG Washington DC Environmental Protection Agency Available at httpwwwfueleconomygovfegfactorsshtml

22 EPA (2009) Detailed Test Information Washington DC Environmental Protection Agency Available at httpwwwfueleconomygovfegfe_test_schedulesshtml

23 CFR sect 86162ndash00 Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2 Washington DC Code of Federal Regulations httpedocketaccessgpogovcfr_2008julqtrpdf40cfr86162-00pdf

24 NHTSA (2009) Tire Ratings Washington DC National Highway Traffic Safety Administration Available at httpwwwsafercargov

25 NHTSA Tire Ratings 26 Grosch K A amp Schallamach A (1961) Tyre Wear at Controlled Slip Wear 4 pp 356 ndash

371 27 National Research Council 28 NHTSA (2001) Tire Pressure Special Study - Vehicle Observation Data August 2001 DOT

HS 809 317 Washington DC National Highway Traffic Safety Administration 29 NHTSA (2009) Tire Pressure Maintenance ndash A Statistical Investigation April 2009 DOT

HS 811 086 Washington DC National Highway Traffic Safety Administration 30 Wicks F amp Sheets W (1991) ldquoEffect of Tire Pressure and Performance Upon Oil Use and

Energy Policy Optionsrdquo Proceedings of the 26th Intersociety Energy Conversion Engineering Conference IECEC-91 August 4-9 1991 Boston Massachusetts Volume 4 pp 307 La Grange IL American Nuclear Society

31 EPA (2009) Fuel Economy Guide Washington DC Environmental Protection Agency [Website] httpwwwfueleconomygovfegmaintainshtml

32 Clark S K amp Dodge R N (1979) A Handbook for the Rolling Resistance of Pneumatic Tires Prepared for the US Department of Transportation Ann Arbor Regents of the University of Michigan

33 Hall D E amp Moreland J C (2000) Fundamentals of Rolling Resistance Spring 2000 Education Symposium No 47 Basic Tire Technology Passenger and Light Truck Akron OH American Chemical Society

34 Continental Tire (2008 November 17) Government Regulation in Transition ndash Continental Tire Point of View Presentation before the California Energy Commission Available at httpwwwenergycagovtransportationtire_efficiencydocuments2008-11shy17_roundtablepresentationsContinental20Tire20Presentationpdf

35 Grugett B C Martin E R amp Thompson G D (1981) The Effects of Tire Inflation Pressure on Passenger Car Fuel Consumption International Congress and Exposition February 23-27 1981 Paper 810069 SAE Technical Paper Series Warrendale PA Society of Automotive Engineers Inc

36 LaClair p 496 37 National Research Council p 34 38 LaClair p 490 39 Luchini J R (1983) Rolling Resistance Test Methods In Tire Rolling Resistance Rubber

Division Symposia Vol 1 D J Schuring Ed Akron OH American Chemical Society 40 ISO (2009) DIS ISO 28580 Draft International Standard ndash Tyre Rolling Resistance

measurement method ndash single-point test and measurement result correlation ndash designed to

facilitate international cooperation and possibly regulation building Passenger Car Truck and Bus Tyres Geneva Switzerland International Organization for Standardization

41 Schuring D J amp Futamura S (1990) Rolling Loss of Pneumatic Highway Tires in the Eighties Rubber Chemistry and Technology Vol 62 No 3 pp 315ndash367

42 LaClair p 477 43 ISO (2005) ISO 18164 T Passenger car truck bus and motorcycle tyres mdash Methods of

measuring rolling resistance Geneva Switzerland International Organization for Standardization

44 Clark amp Dodge p7 45 Clark amp Dodge p7 46 SAE (2006) J1269 - Surface Vehicle Recommended Practice for Rolling Resistance

Measurement Procedure for Passenger Car Light Truck and Highway Truck and Bus Tires Issued 1979-11 Revised 2006-09 Superseding J1269 SEP2000 p 5 Warrendale PA Society of Automotive Engineers

47 SAE (2006) J2452 - Surface Vehicle Recommended Practice for Stepwise Coastdown Methodology for Measuring Tire Rolling Resistance Issued 1999-06 p 8 Warrendale PA Society of Automotive Engineers

48 Lambillotte B (2009 February 5) California Energy Commissionrsquos Fuel Efficient Tire Program PowerPoint Presentation Akron OH Smithers Scientific Services Inc

49 Schuring amp Futamura pp 315ndash367 50 The Tire Rack (2009) Tire Tech InformationGeneral Tire Information P-Metric and Euro

Metric Tire Sizing httpwwwtirerackcomtirestiretechtechpagejsptechid=24 51 Rubber Manufacturers Association (2009) Comments TN-48720pdf to the April 8 2009

California Energy Commission Staff Workshop on the Fuel Efficient Tire Program httpwwwenergycagovtransportationtire_efficiencydocuments2009-04shy08_workshopcomments

52 National Research Council p 78 53 Pillai PS (1995) Total Tire Energy Loss Comparison by the Whole Tire Hysteresis and the

Rolling Resistance Methods Tire Science and Technology TSTCA Vol 23 No 4 pp 256-265

54 The Tire amp Rim Association (2004) Engineering Design Information for Ground Vehicle Tires Pages 1-11 amp 1-15 Rev 5 httpwwwus-traorgtraPubshtml

DOT HS 811 154August 2009

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

This publication is distributed by the US Department of Transportation National Highway TrafficSafetyAdministration in the interestof informationexchangeTheopinionsfindingsand conclusions expressed in this publication are those of the author(s) and not necessarily those of the Department of Transportation or the National Highway Traffic Safety Administration The United States Government assumes no liability for its content or use thereof If trade or manufacturersrsquo names or products are mentioned it is because they are considered essential to the object of the publication and should not be construed as an endorsement The United States Government does not endorse products or manufacturers

5 Report Date

7 Author(s)

DTNH22-03-D-08660 DTNH22-07-D-00060

153 22 Price

LENGTH

MASS (weight)

PRESSURE

VELOCITY

ACCELERATION

TEMPERATURE (exact)

LENGTH

MASS (weight)

PRESSURE

VELOCITY

ACCELERATION

20 METHODOLOGY 7

30 RESULTS 28

40 CONCLUSIONS 78

50 REQUIREMENTS 79

62 DISCUSSION 94

Resistance 61

DEFINITIONS

EXECUTIVE SUMMARY

10 INTRODUCTION

Rolling Resistance

Traction

Treadwear

20 METHODOLOGY

21 Test Tires

947 736 220

983 744 229

1002 758 245

1013 787 251

1127 919 192

1196 930 255

1207 913 247

1209 946 204

1356 1026 252

1390 1080 286

360 A B Run Flat 1391 1052 364

1402 1089 257

1498 1133 243

1501 1166 294

1522 1151 274

Ft = Spindle Force

17 meter Drum

80 grit Surface

T = torque

Fr = TtR-Fpl

24 Test Wheels

25 Test Matrix

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

SRTT 1196 x x x x x

REVO1 1211 x x x

1356 x x x

1390 x x x

1391 x x x

1498 x x x

1501 x x x x x

1522 x x x

Polymer 40

20 Carbon Black

Polymer (325-550C)

phr (550shy

Total Filler phr

Silica phr

Total Formulation

Tire Type

Polymer (325-550C)

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

-150 -100 -50 0 50 100

Temperatue (C)

-100 -50 0 50 100

Temperature (deg C)

Rolling Resistance

0degC Tan at

60degC Ratio 060

Test Schedule

High Speed (US06)

Max Accelshyeration

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Lab temshyperature

Off Off Off On Off

1522 274

947 220

1 Fy 25Fz sin t

30 RESULTS

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

Date Group

Number Description

93008111808

112008 112508

011309 012309

102108 110608

120208 121708

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

0925213 0745556 0271294 3638816

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Alpha 005

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Average 00088

ISO 28580 RR lbs

39720 39740 39760 39780 39800 39820 39840

Test Data Excluded

gt F R2 Value

Probability gt |t|

Variability CV

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

80 90 100 110 120 130

Average 0308

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

006 008 010 012 014 016 018 020 022

OE Run-Flat Tire

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

sistance

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Tire Type

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

R2 = 05175

9 10 11 12 13 14 15 1

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

016 018 020 022 024 026 028 030 032 034 036 038 040

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

Non-Linear Behavior

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Rolling Resistance

9 10 11 12 13 14 15 16

Average Miles

Minimum Miles

9 10 11 12 13 14 15 16

Average

Fastest

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

0801276 1484057 2249727 1515930

Intercept -9197417585 7075025908 -130 02845

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

250 350 450 550 650 750

read Severe

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

016 065

115 164

ht 9384

40 CONCLUSIONS

50 REQUIREMENTS

20 21 22 23 24 25 26 27 28 29 30 094

Passenger

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Pr+70 kPa

Pr -50 kPa capped

Pr -30 kPa

40 50 60 70 90

Pr+70 kPa

TP 1 TP 3

TP 2Pr -30 kPa

Cr = FrLm

210 kPa capped

Theoretical Fr

Tire B

Tire A

Theoretical Cr

Tire B

(Dimensionless)

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

600 800 1000 1200 1400 1600

62 Discussion

75 85 95 105 115 125

Load Index

75 85 95 105 115 125

Load Index

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

Outdoor Tread-wear

Grand Total

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

1 1 1 3

52 48 32 20 32 184

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

RE750 22560R16 588 07 599 576 959 30 1020 924

22560R16 594 08 612 583 961 27 1010 925

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Tire Number

Test Number

Slide Coefficient

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

3343 080180 0830033 No brand name

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Tire Number

Number

Tire Line

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Number

Tire Line

REFERENCES

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

5 Report Date

7 Author(s)

DTNH22-03-D-08660 DTNH22-07-D-00060

153 22 Price

LENGTH

MASS (weight)

PRESSURE

VELOCITY

ACCELERATION

TEMPERATURE (exact)

LENGTH

MASS (weight)

PRESSURE

VELOCITY

ACCELERATION

20 METHODOLOGY 7

30 RESULTS 28

40 CONCLUSIONS 78

50 REQUIREMENTS 79

62 DISCUSSION 94

Resistance 61

DEFINITIONS

EXECUTIVE SUMMARY

10 INTRODUCTION

Rolling Resistance

Traction

Treadwear

20 METHODOLOGY

21 Test Tires

947 736 220

983 744 229

1002 758 245

1013 787 251

1127 919 192

1196 930 255

1207 913 247

1209 946 204

1356 1026 252

1390 1080 286

360 A B Run Flat 1391 1052 364

1402 1089 257

1498 1133 243

1501 1166 294

1522 1151 274

Ft = Spindle Force

17 meter Drum

80 grit Surface

T = torque

Fr = TtR-Fpl

24 Test Wheels

25 Test Matrix

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

SRTT 1196 x x x x x

REVO1 1211 x x x

1356 x x x

1390 x x x

1391 x x x

1498 x x x

1501 x x x x x

1522 x x x

Polymer 40

20 Carbon Black

Polymer (325-550C)

phr (550shy

Total Filler phr

Silica phr

Total Formulation

Tire Type

Polymer (325-550C)

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

-150 -100 -50 0 50 100

Temperatue (C)

-100 -50 0 50 100

Temperature (deg C)

Rolling Resistance

0degC Tan at

60degC Ratio 060

Test Schedule

High Speed (US06)

Max Accelshyeration

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Lab temshyperature

Off Off Off On Off

1522 274

947 220

1 Fy 25Fz sin t

30 RESULTS

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

Date Group

Number Description

93008111808

112008 112508

011309 012309

102108 110608

120208 121708

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

0925213 0745556 0271294 3638816

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Alpha 005

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Average 00088

ISO 28580 RR lbs

39720 39740 39760 39780 39800 39820 39840

Test Data Excluded

gt F R2 Value

Probability gt |t|

Variability CV

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

80 90 100 110 120 130

Average 0308

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

006 008 010 012 014 016 018 020 022

OE Run-Flat Tire

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

sistance

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Tire Type

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

R2 = 05175

9 10 11 12 13 14 15 1

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

016 018 020 022 024 026 028 030 032 034 036 038 040

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

Non-Linear Behavior

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Rolling Resistance

9 10 11 12 13 14 15 16

Average Miles

Minimum Miles

9 10 11 12 13 14 15 16

Average

Fastest

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

0801276 1484057 2249727 1515930

Intercept -9197417585 7075025908 -130 02845

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

250 350 450 550 650 750

read Severe

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

016 065

115 164

ht 9384

40 CONCLUSIONS

50 REQUIREMENTS

20 21 22 23 24 25 26 27 28 29 30 094

Passenger

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Pr+70 kPa

Pr -50 kPa capped

Pr -30 kPa

40 50 60 70 90

Pr+70 kPa

TP 1 TP 3

TP 2Pr -30 kPa

Cr = FrLm

210 kPa capped

Theoretical Fr

Tire B

Tire A

Theoretical Cr

Tire B

(Dimensionless)

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

600 800 1000 1200 1400 1600

62 Discussion

75 85 95 105 115 125

Load Index

75 85 95 105 115 125

Load Index

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

Outdoor Tread-wear

Grand Total

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

1 1 1 3

52 48 32 20 32 184

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

RE750 22560R16 588 07 599 576 959 30 1020 924

22560R16 594 08 612 583 961 27 1010 925

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Tire Number

Test Number

Slide Coefficient

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

3343 080180 0830033 No brand name

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Tire Number

Number

Tire Line

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Number

Tire Line

REFERENCES

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

LENGTH

MASS (weight)

PRESSURE

VELOCITY

ACCELERATION

TEMPERATURE (exact)

LENGTH

MASS (weight)

PRESSURE

VELOCITY

ACCELERATION

20 METHODOLOGY 7

30 RESULTS 28

40 CONCLUSIONS 78

50 REQUIREMENTS 79

62 DISCUSSION 94

Resistance 61

DEFINITIONS

EXECUTIVE SUMMARY

10 INTRODUCTION

Rolling Resistance

Traction

Treadwear

20 METHODOLOGY

21 Test Tires

947 736 220

983 744 229

1002 758 245

1013 787 251

1127 919 192

1196 930 255

1207 913 247

1209 946 204

1356 1026 252

1390 1080 286

360 A B Run Flat 1391 1052 364

1402 1089 257

1498 1133 243

1501 1166 294

1522 1151 274

Ft = Spindle Force

17 meter Drum

80 grit Surface

T = torque

Fr = TtR-Fpl

24 Test Wheels

25 Test Matrix

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

SRTT 1196 x x x x x

REVO1 1211 x x x

1356 x x x

1390 x x x

1391 x x x

1498 x x x

1501 x x x x x

1522 x x x

Polymer 40

20 Carbon Black

Polymer (325-550C)

phr (550shy

Total Filler phr

Silica phr

Total Formulation

Tire Type

Polymer (325-550C)

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

-150 -100 -50 0 50 100

Temperatue (C)

-100 -50 0 50 100

Temperature (deg C)

Rolling Resistance

0degC Tan at

60degC Ratio 060

Test Schedule

High Speed (US06)

Max Accelshyeration

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Lab temshyperature

Off Off Off On Off

1522 274

947 220

1 Fy 25Fz sin t

30 RESULTS

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

Date Group

Number Description

93008111808

112008 112508

011309 012309

102108 110608

120208 121708

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

0925213 0745556 0271294 3638816

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Alpha 005

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Average 00088

ISO 28580 RR lbs

39720 39740 39760 39780 39800 39820 39840

Test Data Excluded

gt F R2 Value

Probability gt |t|

Variability CV

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

80 90 100 110 120 130

Average 0308

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

006 008 010 012 014 016 018 020 022

OE Run-Flat Tire

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

sistance

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Tire Type

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

R2 = 05175

9 10 11 12 13 14 15 1

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

016 018 020 022 024 026 028 030 032 034 036 038 040

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

Non-Linear Behavior

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Rolling Resistance

9 10 11 12 13 14 15 16

Average Miles

Minimum Miles

9 10 11 12 13 14 15 16

Average

Fastest

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

0801276 1484057 2249727 1515930

Intercept -9197417585 7075025908 -130 02845

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

250 350 450 550 650 750

read Severe

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

016 065

115 164

ht 9384

40 CONCLUSIONS

50 REQUIREMENTS

20 21 22 23 24 25 26 27 28 29 30 094

Passenger

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Pr+70 kPa

Pr -50 kPa capped

Pr -30 kPa

40 50 60 70 90

Pr+70 kPa

TP 1 TP 3

TP 2Pr -30 kPa

Cr = FrLm

210 kPa capped

Theoretical Fr

Tire B

Tire A

Theoretical Cr

Tire B

(Dimensionless)

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

600 800 1000 1200 1400 1600

62 Discussion

75 85 95 105 115 125

Load Index

75 85 95 105 115 125

Load Index

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

Outdoor Tread-wear

Grand Total

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

1 1 1 3

52 48 32 20 32 184

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

RE750 22560R16 588 07 599 576 959 30 1020 924

22560R16 594 08 612 583 961 27 1010 925

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Tire Number

Test Number

Slide Coefficient

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

3343 080180 0830033 No brand name

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Tire Number

Number

Tire Line

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Number

Tire Line

REFERENCES

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

20 METHODOLOGY 7

30 RESULTS 28

40 CONCLUSIONS 78

50 REQUIREMENTS 79

62 DISCUSSION 94

Resistance 61

DEFINITIONS

EXECUTIVE SUMMARY

10 INTRODUCTION

Rolling Resistance

Traction

Treadwear

20 METHODOLOGY

21 Test Tires

947 736 220

983 744 229

1002 758 245

1013 787 251

1127 919 192

1196 930 255

1207 913 247

1209 946 204

1356 1026 252

1390 1080 286

360 A B Run Flat 1391 1052 364

1402 1089 257

1498 1133 243

1501 1166 294

1522 1151 274

Ft = Spindle Force

17 meter Drum

80 grit Surface

T = torque

Fr = TtR-Fpl

24 Test Wheels

25 Test Matrix

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

SRTT 1196 x x x x x

REVO1 1211 x x x

1356 x x x

1390 x x x

1391 x x x

1498 x x x

1501 x x x x x

1522 x x x

Polymer 40

20 Carbon Black

Polymer (325-550C)

phr (550shy

Total Filler phr

Silica phr

Total Formulation

Tire Type

Polymer (325-550C)

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

-150 -100 -50 0 50 100

Temperatue (C)

-100 -50 0 50 100

Temperature (deg C)

Rolling Resistance

0degC Tan at

60degC Ratio 060

Test Schedule

High Speed (US06)

Max Accelshyeration

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Lab temshyperature

Off Off Off On Off

1522 274

947 220

1 Fy 25Fz sin t

30 RESULTS

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

Date Group

Number Description

93008111808

112008 112508

011309 012309

102108 110608

120208 121708

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

0925213 0745556 0271294 3638816

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Alpha 005

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Average 00088

ISO 28580 RR lbs

39720 39740 39760 39780 39800 39820 39840

Test Data Excluded

gt F R2 Value

Probability gt |t|

Variability CV

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

80 90 100 110 120 130

Average 0308

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

006 008 010 012 014 016 018 020 022

OE Run-Flat Tire

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

sistance

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Tire Type

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

R2 = 05175

9 10 11 12 13 14 15 1

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

016 018 020 022 024 026 028 030 032 034 036 038 040

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

Non-Linear Behavior

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Rolling Resistance

9 10 11 12 13 14 15 16

Average Miles

Minimum Miles

9 10 11 12 13 14 15 16

Average

Fastest

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

0801276 1484057 2249727 1515930

Intercept -9197417585 7075025908 -130 02845

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

250 350 450 550 650 750

read Severe

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

016 065

115 164

ht 9384

40 CONCLUSIONS

50 REQUIREMENTS

20 21 22 23 24 25 26 27 28 29 30 094

Passenger

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Pr+70 kPa

Pr -50 kPa capped

Pr -30 kPa

40 50 60 70 90

Pr+70 kPa

TP 1 TP 3

TP 2Pr -30 kPa

Cr = FrLm

210 kPa capped

Theoretical Fr

Tire B

Tire A

Theoretical Cr

Tire B

(Dimensionless)

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

600 800 1000 1200 1400 1600

62 Discussion

75 85 95 105 115 125

Load Index

75 85 95 105 115 125

Load Index

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

Outdoor Tread-wear

Grand Total

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

1 1 1 3

52 48 32 20 32 184

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

RE750 22560R16 588 07 599 576 959 30 1020 924

22560R16 594 08 612 583 961 27 1010 925

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Tire Number

Test Number

Slide Coefficient

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

3343 080180 0830033 No brand name

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Tire Number

Number

Tire Line

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Number

Tire Line

REFERENCES

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

Resistance 61

DEFINITIONS

EXECUTIVE SUMMARY

10 INTRODUCTION

Rolling Resistance

Traction

Treadwear

20 METHODOLOGY

21 Test Tires

947 736 220

983 744 229

1002 758 245

1013 787 251

1127 919 192

1196 930 255

1207 913 247

1209 946 204

1356 1026 252

1390 1080 286

360 A B Run Flat 1391 1052 364

1402 1089 257

1498 1133 243

1501 1166 294

1522 1151 274

Ft = Spindle Force

17 meter Drum

80 grit Surface

T = torque

Fr = TtR-Fpl

24 Test Wheels

25 Test Matrix

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

SRTT 1196 x x x x x

REVO1 1211 x x x

1356 x x x

1390 x x x

1391 x x x

1498 x x x

1501 x x x x x

1522 x x x

Polymer 40

20 Carbon Black

Polymer (325-550C)

phr (550shy

Total Filler phr

Silica phr

Total Formulation

Tire Type

Polymer (325-550C)

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

-150 -100 -50 0 50 100

Temperatue (C)

-100 -50 0 50 100

Temperature (deg C)

Rolling Resistance

0degC Tan at

60degC Ratio 060

Test Schedule

High Speed (US06)

Max Accelshyeration

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Lab temshyperature

Off Off Off On Off

1522 274

947 220

1 Fy 25Fz sin t

30 RESULTS

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

Date Group

Number Description

93008111808

112008 112508

011309 012309

102108 110608

120208 121708

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

0925213 0745556 0271294 3638816

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Alpha 005

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Average 00088

ISO 28580 RR lbs

39720 39740 39760 39780 39800 39820 39840

Test Data Excluded

gt F R2 Value

Probability gt |t|

Variability CV

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

80 90 100 110 120 130

Average 0308

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

006 008 010 012 014 016 018 020 022

OE Run-Flat Tire

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

sistance

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Tire Type

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

R2 = 05175

9 10 11 12 13 14 15 1

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

016 018 020 022 024 026 028 030 032 034 036 038 040

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

Non-Linear Behavior

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Rolling Resistance

9 10 11 12 13 14 15 16

Average Miles

Minimum Miles

9 10 11 12 13 14 15 16

Average

Fastest

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

0801276 1484057 2249727 1515930

Intercept -9197417585 7075025908 -130 02845

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

250 350 450 550 650 750

read Severe

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

016 065

115 164

ht 9384

40 CONCLUSIONS

50 REQUIREMENTS

20 21 22 23 24 25 26 27 28 29 30 094

Passenger

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Pr+70 kPa

Pr -50 kPa capped

Pr -30 kPa

40 50 60 70 90

Pr+70 kPa

TP 1 TP 3

TP 2Pr -30 kPa

Cr = FrLm

210 kPa capped

Theoretical Fr

Tire B

Tire A

Theoretical Cr

Tire B

(Dimensionless)

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

600 800 1000 1200 1400 1600

62 Discussion

75 85 95 105 115 125

Load Index

75 85 95 105 115 125

Load Index

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

Outdoor Tread-wear

Grand Total

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

1 1 1 3

52 48 32 20 32 184

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

RE750 22560R16 588 07 599 576 959 30 1020 924

22560R16 594 08 612 583 961 27 1010 925

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Tire Number

Test Number

Slide Coefficient

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

3343 080180 0830033 No brand name

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Tire Number

Number

Tire Line

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Number

Tire Line

REFERENCES

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

Resistance 61

DEFINITIONS

EXECUTIVE SUMMARY

10 INTRODUCTION

Rolling Resistance

Traction

Treadwear

20 METHODOLOGY

21 Test Tires

947 736 220

983 744 229

1002 758 245

1013 787 251

1127 919 192

1196 930 255

1207 913 247

1209 946 204

1356 1026 252

1390 1080 286

360 A B Run Flat 1391 1052 364

1402 1089 257

1498 1133 243

1501 1166 294

1522 1151 274

Ft = Spindle Force

17 meter Drum

80 grit Surface

T = torque

Fr = TtR-Fpl

24 Test Wheels

25 Test Matrix

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

SRTT 1196 x x x x x

REVO1 1211 x x x

1356 x x x

1390 x x x

1391 x x x

1498 x x x

1501 x x x x x

1522 x x x

Polymer 40

20 Carbon Black

Polymer (325-550C)

phr (550shy

Total Filler phr

Silica phr

Total Formulation

Tire Type

Polymer (325-550C)

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

-150 -100 -50 0 50 100

Temperatue (C)

-100 -50 0 50 100

Temperature (deg C)

Rolling Resistance

0degC Tan at

60degC Ratio 060

Test Schedule

High Speed (US06)

Max Accelshyeration

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Lab temshyperature

Off Off Off On Off

1522 274

947 220

1 Fy 25Fz sin t

30 RESULTS

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

Date Group

Number Description

93008111808

112008 112508

011309 012309

102108 110608

120208 121708

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

0925213 0745556 0271294 3638816

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Alpha 005

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Average 00088

ISO 28580 RR lbs

39720 39740 39760 39780 39800 39820 39840

Test Data Excluded

gt F R2 Value

Probability gt |t|

Variability CV

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

80 90 100 110 120 130

Average 0308

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

006 008 010 012 014 016 018 020 022

OE Run-Flat Tire

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

sistance

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Tire Type

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

R2 = 05175

9 10 11 12 13 14 15 1

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

016 018 020 022 024 026 028 030 032 034 036 038 040

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

Non-Linear Behavior

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Rolling Resistance

9 10 11 12 13 14 15 16

Average Miles

Minimum Miles

9 10 11 12 13 14 15 16

Average

Fastest

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

0801276 1484057 2249727 1515930

Intercept -9197417585 7075025908 -130 02845

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

250 350 450 550 650 750

read Severe

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

016 065

115 164

ht 9384

40 CONCLUSIONS

50 REQUIREMENTS

20 21 22 23 24 25 26 27 28 29 30 094

Passenger

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Pr+70 kPa

Pr -50 kPa capped

Pr -30 kPa

40 50 60 70 90

Pr+70 kPa

TP 1 TP 3

TP 2Pr -30 kPa

Cr = FrLm

210 kPa capped

Theoretical Fr

Tire B

Tire A

Theoretical Cr

Tire B

(Dimensionless)

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

600 800 1000 1200 1400 1600

62 Discussion

75 85 95 105 115 125

Load Index

75 85 95 105 115 125

Load Index

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

Outdoor Tread-wear

Grand Total

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

1 1 1 3

52 48 32 20 32 184

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

RE750 22560R16 588 07 599 576 959 30 1020 924

22560R16 594 08 612 583 961 27 1010 925

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Tire Number

Test Number

Slide Coefficient

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

3343 080180 0830033 No brand name

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Tire Number

Number

Tire Line

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Number

Tire Line

REFERENCES

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

DEFINITIONS

EXECUTIVE SUMMARY

10 INTRODUCTION

Rolling Resistance

Traction

Treadwear

20 METHODOLOGY

21 Test Tires

947 736 220

983 744 229

1002 758 245

1013 787 251

1127 919 192

1196 930 255

1207 913 247

1209 946 204

1356 1026 252

1390 1080 286

360 A B Run Flat 1391 1052 364

1402 1089 257

1498 1133 243

1501 1166 294

1522 1151 274

Ft = Spindle Force

17 meter Drum

80 grit Surface

T = torque

Fr = TtR-Fpl

24 Test Wheels

25 Test Matrix

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

SRTT 1196 x x x x x

REVO1 1211 x x x

1356 x x x

1390 x x x

1391 x x x

1498 x x x

1501 x x x x x

1522 x x x

Polymer 40

20 Carbon Black

Polymer (325-550C)

phr (550shy

Total Filler phr

Silica phr

Total Formulation

Tire Type

Polymer (325-550C)

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

-150 -100 -50 0 50 100

Temperatue (C)

-100 -50 0 50 100

Temperature (deg C)

Rolling Resistance

0degC Tan at

60degC Ratio 060

Test Schedule

High Speed (US06)

Max Accelshyeration

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Lab temshyperature

Off Off Off On Off

1522 274

947 220

1 Fy 25Fz sin t

30 RESULTS

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

Date Group

Number Description

93008111808

112008 112508

011309 012309

102108 110608

120208 121708

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

0925213 0745556 0271294 3638816

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Alpha 005

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Average 00088

ISO 28580 RR lbs

39720 39740 39760 39780 39800 39820 39840

Test Data Excluded

gt F R2 Value

Probability gt |t|

Variability CV

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

80 90 100 110 120 130

Average 0308

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

006 008 010 012 014 016 018 020 022

OE Run-Flat Tire

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

sistance

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Tire Type

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

R2 = 05175

9 10 11 12 13 14 15 1

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

016 018 020 022 024 026 028 030 032 034 036 038 040

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

Non-Linear Behavior

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Rolling Resistance

9 10 11 12 13 14 15 16

Average Miles

Minimum Miles

9 10 11 12 13 14 15 16

Average

Fastest

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

0801276 1484057 2249727 1515930

Intercept -9197417585 7075025908 -130 02845

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

250 350 450 550 650 750

read Severe

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

016 065

115 164

ht 9384

40 CONCLUSIONS

50 REQUIREMENTS

20 21 22 23 24 25 26 27 28 29 30 094

Passenger

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Pr+70 kPa

Pr -50 kPa capped

Pr -30 kPa

40 50 60 70 90

Pr+70 kPa

TP 1 TP 3

TP 2Pr -30 kPa

Cr = FrLm

210 kPa capped

Theoretical Fr

Tire B

Tire A

Theoretical Cr

Tire B

(Dimensionless)

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

600 800 1000 1200 1400 1600

62 Discussion

75 85 95 105 115 125

Load Index

75 85 95 105 115 125

Load Index

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

Outdoor Tread-wear

Grand Total

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

1 1 1 3

52 48 32 20 32 184

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

RE750 22560R16 588 07 599 576 959 30 1020 924

22560R16 594 08 612 583 961 27 1010 925

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Tire Number

Test Number

Slide Coefficient

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

3343 080180 0830033 No brand name

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Tire Number

Number

Tire Line

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Number

Tire Line

REFERENCES

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

DEFINITIONS

EXECUTIVE SUMMARY

10 INTRODUCTION

Rolling Resistance

Traction

Treadwear

20 METHODOLOGY

21 Test Tires

947 736 220

983 744 229

1002 758 245

1013 787 251

1127 919 192

1196 930 255

1207 913 247

1209 946 204

1356 1026 252

1390 1080 286

360 A B Run Flat 1391 1052 364

1402 1089 257

1498 1133 243

1501 1166 294

1522 1151 274

Ft = Spindle Force

17 meter Drum

80 grit Surface

T = torque

Fr = TtR-Fpl

24 Test Wheels

25 Test Matrix

Index Speed Rating

Model RR (lbf)

Dyno FE

Wet amp Dry

Traction

On-vehicle

Treadwear

Indoor Treadwear

SRTT 1196 x x x x x

REVO1 1211 x x x

1356 x x x

1390 x x x

1391 x x x

1498 x x x

1501 x x x x x

1522 x x x

Polymer 40

20 Carbon Black

Polymer (325-550C)

phr (550shy

Total Filler phr

Silica phr

Total Formulation

Tire Type

Polymer (325-550C)

P5 3670 471 29 79 4 79 0 206 R4 3695 483 30 42 35 71 29 201 M14 3720 55 19 30 32 57 26 176

-150 -100 -50 0 50 100

Temperatue (C)

-100 -50 0 50 100

Temperature (deg C)

Rolling Resistance

0degC Tan at

60degC Ratio 060

Test Schedule

High Speed (US06)

Max Accelshyeration

Simulated Distance

11 mi 103 mi 8 mi 36 mi 11 mi

Lab temshyperature

Off Off Off On Off

1522 274

947 220

1 Fy 25Fz sin t

30 RESULTS

093008 M146 210 1196 213 359 368 362 193 219 100108 B11 210 1013 213 367 371 368 196 221 100208 B13 210 1502 208 348 354 346 186 211 100608 B13 158 15587 203 343 352 346 185 209 100708 G8 158 1045 214 365 372 366 193 222 100808 M13 210 1206 211 358 363 360 194 219 100908 M14 158 1247 211 359 365 361 193 219 101008 G8 210 983 219 373 382 378 199 224 101308 M13 158 1260 211 355 364 357 193 219 101408 B11 158 1080 213 363 371 363 193 219 101508 M14 210 1196 214 362 367 364 193 217 101608 G12 210 947 217 375 382 378 201 224 101708 G12 158 1009 212 365 373 367 194 223

102108 M14 210 1196 188 102208 M14 158 1247 184 102308 B11 210 1013 190 102408 B11 158 1080 188 102508 B13 158 1558 181 102708 B13 210 1501 184 102808 G8 210 983 190 103008 M13 158 1260 183 103108 M13 210 1206 187 110308 G8 158 1045 189 110508 G12 210 947 193 110608 G12 158 1009

120208 M14 210 1196 191 120308 B10 210 1211 191 120408 B12 210 1522 183 120508 B14 210 1390 185 120608 D10 210 1356

Legend

120808 B15 210 1399 182 121008 U3 210 1391 182 121108 G11 210 1002 190 121208 P5 210 1402 185 121508 R4 210 1498 184 121608 G12 210 947 186 121708 M14 210 1196 188 011309 M14 210 1196 217 372 370 371 011409 M14 210 1196 217 373 373 375 198 219 011509 G12 210 947 221 378 378 379 203 225 011909 B13 210 1501 206 360 357 359 195 208 012109 G11 210 1002 221 380 383 379 204 226 012209 P5 210 1402 214 362 367 369 196 209 012309 R4 210 1498 212 363 367 365 196 208

Date Group

Number Description

93008111808

112008 112508

011309 012309

102108 110608

120208 121708

Microsoft Date Code

39720 39730 39740 39750 39760 39770

Model 23 1006797092 43773787 594749 lt0001

Error 53 39008 00736

0925213 0745556 0271294 3638816

type 20 4059476016 202973801 2758 lt0001

bag 2 764826645 382413323 5196 lt0001

Alpha 005

A 3681923 26 2

B 3624400 25 3

C 3608400 25 1

mpg 093008 193 101508 193 101708 194 111008 200

112408 219

112508 219

011409 198

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Average 00088

ISO 28580 RR lbs

39720 39740 39760 39780 39800 39820 39840

Test Data Excluded

gt F R2 Value

Probability gt |t|

Variability CV

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

202 204 206 208 210 212 214 216 218 220 222

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

184 186 188 190 192 194 196 198 200 202 204

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

181 182 183 184 185 186 187 188 189 190 191 192 193

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

80 90 100 110 120 130

Average 0308

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

B 1 1 L

B 1 3 L

G 1 2 L

M 1 3 L

M 1 4 L

ISO 28580 RR lbs

9 10 11 12 13 14 15 16

Rolling Resistance

006 008 010 012 014 016 018 020 022

OE Run-Flat Tire

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 9441 95 6595 110 9325 88 7531 95 G11 1002 9745 99 6466 93 10407 96 7595 93 B11 1013 9477 96 6073 98 10112 93 7443 91 G9 1127 9825 98 7416 109 10220 95 7882 97

M14 1196 9953 101 6667 104 10550 97 8170 100 M13 1207 10012 101 5375 82 10562 97 6966 85 G10 1209 9853 96 7400 101 10207 94 7839 97 B10 1211 9383 94 7765 127 9645 91 8663 107 D10 1356 9460 95 6210 101 10271 96 7477 94 B14 1390 10150 102 7576 125 10758 100 8502 106 U3 1391 9175 94 6723 108 10022 93 7971 103 B15 1399 9064 92 6699 107 9193 86 7542 97 P5 1402 9561 95 5697 96 9463 90 7152 92 R4 1498 10419 106 7113 112 10786 103 8438 104 B13 1501 9487 94 5763 96 9193 88 7642 98 B12 1522 10390 106 5633 89 10818 102 7195 88

E501 - 9923 100 6348 100 10715 100 8032 100

sistance

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

0209 0200 -0158 0045 0056 0209 0069 0217 Probability gt |r| 02518 02730 03886 08073 07602 02507 07059 02336

R2 = 00033

R2 = 0044

R2 = 00058

R2 = 00241

9 10 11 12 13 14 15 16

R2 = 00003

R2 = 0047

R2 = 00445

R2 = 00469

9 10 11 12 13 14 15 16

Tire Type

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

G8 983 876 101 489 93 589 103 351 100 G11 1002 829 96 499 95 634 111 366 104 B11 1013 872 102 464 90 630 110 364 99 G9 1127 822 101 547 102 586 102 364 102

M14 1196 948 104 588 109 662 116 396 109 M13 1207 938 103 509 97 734 132 401 111 G10 1209 835 105 551 101 563 106 367 103 B10 1211 800 95 495 92 486 90 374 104 D10 1356 893 106 545 100 682 122 395 109 B14 1390 944 108 589 111 762 128 422 115 U3 1391 875 100 537 100 649 109 402 109 B15 1399 793 94 524 97 541 101 354 98 P5 1402 841 99 543 105 702 124 410 112 R4 1498 869 103 605 111 645 115 391 107 B13 1501 923 105 577 108 711 120 410 111 B12 1522 960 118 591 110 801 140 423 119

E501 - 858 100 533 100 564 100 361 100

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

R2 = 00875

R2 = 02116

R2 = 05511

R2 = 05035

9 10 11 12 13 14 15 16

R2 = 02273

R2 = 04133

R2 = 0524

R2 = 01657

9 10 11 12 13 14 15 16

R2 = 05175

9 10 11 12 13 14 15 1

R2 = 0405

9 10 11 12 13 14 15 1

uc ) A

016 018 020 022 024 026 028 030 032 034 036 038 040

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

Traction Number

Ratio E501

06653 08119 08432 08635 07381 07536 08375 08556 Probability gt

|r| 00049 00001 lt00001 lt00001 00011 00007 lt00001 lt00001

Non-Linear Behavior

B11 1013 5155 54840 5752 4528 48550 63200 B13 1501 6463 52020 6374 6276 51790 54540 G8 983 6447 45390 6211 6471 46460 45840

M13 1207 5448 41310 4795 5768 45150 40500 M14 1196 5558 45000 4359 6449 56730 39230

Rolling Resistance

9 10 11 12 13 14 15 16

Average Miles

Minimum Miles

9 10 11 12 13 14 15 16

Average

Fastest

B11 1031 288 33 32 B13 424 179 24 26 G8 1015 371 23 16

G12 573 NA 31 NA M13 288 127 12 09 M14 368 163 14 18

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

9 10 11 12 13 14 15

Severe - Center

Severe - Shoulder

Mild - Center

Mild = Shoulder

Model 1 6122287064 6122287064 1210 00401

Error 3 1518381257 506127086

0801276 1484057 2249727 1515930

Intercept -9197417585 7075025908 -130 02845

Model 1 5827698651 5827698651 2846 00005

Error 9 1843064535 204784948

0759729 2053616 1431031 6968346

Intercept -6990936132 2652091689 -264 00271

Model 1 1199395624 1199395624 148 03114

Error 3 2439125865 813041955

0329638 3582655 2851389 7958872

Intercept -2821735065 8967155960 -031 07736

Model 1 1502464861 1502464861 528 00472

Error 9 2562684014 284742668

0369597 4839223 1687432 3486990

Intercept -3600895727 3127272986 -115 02792

250 350 450 550 650 750

read Severe

RR lbs

Tire Weight lbs

42 43 44 45 46 47 48 49 50 51 52

Weight Loss lbs

00 02 04 06 08 10 12 14 16 18

Model 2 233716819 116858410 305 00581

Error 41 1569477014 38279927

0129613 1984430 1956526 9859384

Weight Loss 1 041847204 041847204 011 07426

Intercept 9937003782 043386711 22903 lt0001

Weight Loss -035589632 107640530 -033 07426

016 065

115 164

ht 9384

40 CONCLUSIONS

50 REQUIREMENTS

20 21 22 23 24 25 26 27 28 29 30 094

Passenger

02 025 03 035 04 045 05 055 0968

Tire Radius (m)

Pr+70 kPa

Pr -50 kPa capped

Pr -30 kPa

40 50 60 70 90

Pr+70 kPa

TP 1 TP 3

TP 2Pr -30 kPa

Cr = FrLm

210 kPa capped

Theoretical Fr

Tire B

Tire A

Theoretical Cr

Tire B

(Dimensionless)

0 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17

0 200 400 600 800 1000 1200 1400 1600

600 800 1000 1200 1400 1600

62 Discussion

75 85 95 105 115 125

Load Index

75 85 95 105 115 125

Load Index

Sd [034848+06497(A)] x S85 [034848+06497(A)] x S70

A HS85 HS70

Outdoor Tread-wear

Grand Total

3 1 1 5

B11 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

B13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

G8 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 1 1 ISO 18164 1 1

3 1 1 5

M13 J2452 3 1 1 5 J1269 - Single-point

3 1 1 1 6

ISO 28580 2 2 M14 J2452 3 1 1 5

3 1 1 1 6

ISO 28580 1 1 P5 J2452 3 1 1 5

3 1 1 5

1 1 1 3

52 48 32 20 32 184

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

3111 080187 0830096 Bridgestone

3117 080190 0830097 Bridgestone

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

3727 080145 0830076 Uniroyal

3733 080146 0830077 Uniroyal

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 513 13 541 491 947 38 1010 899

22560R16 504 07 512 490 929 18 969 910

P22560R16 583 08 595 571 945 27 983 912

P22560R16 593 05 600 584 952 32 1000 879

RE750 22560R16 588 07 599 576 959 30 1020 924

22560R16 594 08 612 583 961 27 1010 925

REV01 STUDLESS

22560R16 500 07 514 492 808 40 886 752

22560R16 490 06 503 482 792 35 843 728

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 525 05 532 515 784 34 847 739

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 522 07 528 506 802 18 820 771

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 598 07 611 588 869 30 915 827

22560R16 611 06 620 599 870 20 911 849

22560R16 545 07 559 538 899 41 963 840

22560R16 545 08 555 535 887 24 916 842

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 535 08 547 522 886 26 935 839

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 538 05 546 525 864 20 900 834

RE92 P22560R16 457 05 466 449 860 44 898 779

P22560R16 471 06 478 458 883 42 964 818

Tire Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Peak

Low Peak

22560R16 404 09 420 385 718 22 764 687

22560R16 398 08 411 383 750 36 806 705

P22560R16 395 10 405 376 666 21 693 638

P22560R16 396 10 405 370 657 18 702 631

RE750 22560R16 420 11 431 401 793 31 828 732

22560R16 425 11 445 409 808 32 834 737

REV01 STUDLESS

22560R16 374 09 389 362 487 13 509 468

22560R16 373 14 391 352 485 14 512 462

3349 080176 0830032 No brand name

WINTERFORCE 22560R16 355 08 366 341 541 13 562 522

3343 080180 0830033 No brand name

WINTERFORCE 22560R16 352 08 365 335 541 09 555 530

Number

Test Number

STDev Slide

High Slide

Low Slide

Average Peak

STDev Peak

High Low Peak Peak

22560R16 385 09 401 371 645 36 705 589

22560R16 396 10 406 377 646 34 699 596

22560R16 402 20 448 379 685 23 715 648

22560R16 388 13 409 371 679 25 708 643

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 402 12 418 382 648 28 701 612

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 401 11 414 380 650 21 678 624

RE92 P22560R16 360 06 367 348 623 37 682 571

P22560R16 367 07 376 354 636 36 695 578

Tire Number

Test Number

Slide Coefficient

22560R16 0513 0404 049 039 A A

22560R16 0504 0398 048 039 A A

P22560R16 0583 0395 055 038 A AA

P22560R16 0593 0396 056 038 A AA

RE750 22560R16 0588 0420 055 041 AA AA

22560R16 0594 0425 056 042 AA AA

REV01 STUDLESS

22560R16 0500 0374 046 039 none B

22560R16 0490 0373 045 036 none B

3349 080176 0830032 No brand name

3343 080180 0830033 No brand name

SEASONS 22560R16 0598 0385 055 037 A A

Number

Test Number

Slide Coefficient

22560R16 0611 0396 057 038 A AA

22560R16 0545 0402 050 039 A A

22560R16 0545 0388 050 037 A A

3374 080181 0830046 Dunlop SP 4000 DSSST C

P22560R17 0535 0402 050 038 A A

3368 080186 0830047 Dunlop SP 4000 DSSST C

P22560R17 0538 0401 050 038 A A

RE92 P22560R16 0457 0360 044 034 A B

P22560R16 0471 0367 046 035 A B

Tire Number

Number

Tire Line

080022 0831006 ASTM E501

G78-15 518 06 914 37 363 07 566 44

080021 ASTM E501

G78-15 528 06 900 39 361 10 550 59 0830004 0830005 0830008 0830009

0831007

080021 0831012 ASTM E501

G78-15 543 02 919 34 364 10 564 40

080022 ASTM E501

G78-15 533 05 904 45 360 08 572 76 0830010 0830011 0830014 0830015

0831013

080022 0831018 ASTM E501

G78-15 526 04 870 36 353 08 574 56

080021 ASTM E501

G78-15 524 04 861 40 347 07 571 55 0830016 0830017 0830020 0830021

0831019

080021 0831024 ASTM E501

G78-15 542 03 814 14 356 06 577 45

080022 ASTM E501

G78-15 535 06 815 17 357 07 570 33 0830022 0830023 0830026 0830027

0831025

080022 0831030 ASTM E501

G78-15 543 04 848 29 362 06 543 20

080021 ASTM E501

G78-15 536 06 837 31 357 05 531 25 0830028 0830029 0830032 0830033

0831031

080021 0831036 ASTM E501

G78-15 548 06 809 49 356 06 520 37

080022 ASTM E501

G78-15 546 06 780 26 356 05 544 22 0830034 0830035

0831037

080022 0831042 ASTM E501

G78-15 544 06 834 39 366 06 517 36

080021 ASTM E501

G78-15 543 04 853 32 362 04 602 42 0830040 0830041 0830044 0830045

0831043

080021 0831048 ASTM E501

G78-15 542 06 874 46 374 10 596 38

080022 ASTM E501

G78-15 527 04 884 23 365 07 567 49 0830046 0830047 0830050 0830051

0831049

080022 0831054 ASTM E501

G78-15 530 05 872 36 367 05 596 39

080021 ASTM E501

G78-15 530 05 872 36 367 05 596 39 0830052 0830053

0831055

080021 0831058 ASTM E501

G78-15 521 04 846 34 368 04 571 55

080022 ASTM E501

G78-15 510 03 847 37 364 08 564 63 0830056 0830057 0830060 0830061

0831059

Number

Tire Line

REFERENCES

10 INTRODUCTION


20 METHODOLOGY

21 Test Tires







24 Test Wheels

25 Test Matrix










30 RESULTS
















40 CONCLUSIONS

50 REQUIREMENTS








62 Discussion

Documents

NHTSA Tire Fuel Efficiency Consumer Information Program Development