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Welcome!
Professional Societies:
Tire and Rim Association, Motorcycle Sub-Committee, Board Chair, 2011-2013, 2016
Tennessee Highway Patrol, Critical Incident Response Team, Board of Advisors, 2016
Lipscomb University, Engineering Board of Advisors, 2007-Present
Society of Automotive Engineers, Board Chair 2007-2009
Motorcycle Industry Council, 2008-Present
Motorcycle Safety Foundation, Chief Riding Instructor 2015-Present.
Illinois Association of Technical Accident Investigators
Motorcycle Industry Council
• Tennent and Associates
• 615-636-8136
Welcome!!!
T.J. Tennent
TRA Annual Yearbook
The Tire and Rim Association
330-666-8121
Radial Tire Conditions Manual
Radial Tire Conditions Analysis
Guide
703-838-1763
Passenger and Lt Truck
Tire Conditions Manual
PSR and Tt Truck
Tire conditions manual
301-430-7280
AGENDA• Why Tires Are Important
• Tire Performance Requirements
• Tire Construction Basics
• Vehicle Door Placard
• UTQG (Uniform Tire Quality Grading)
• Load Index
• Tire Deflection
• Proper Tire Maintenance
• Tire Repairs
• Air Pressure Effects on Tires
• Tire Application Guidelines
• P-Metric vs Euro-Metric vs Light Truck
WHY ARE TIRES IMPORTANT
• The (4) tires on your vehicle are the only thing making
your cruiser do what you want it to do (accelerate /
brake / corner)
• Maintaining TOTAL CONTROL of your vehicle is as
important to your safety as maintaining total control of
your firearm
• Today's tires are highly complex composite structures
that require proper maintenance
• We need to establish & implement appropriate
maintenance practices for the tires on all our vehicles
TRACTION
TREADWEAR
DURABILITY
RIDE
HANDLING
NOISE
ROLLING RESISTANCE
BRUISE RESISTANCE
CUT RESISTANCE
UNIFORMITY
STATIC-LOADED RADIUS
FLATSPOTTING
OVERTURNING MOMENT
DIMENSIONS
TRACKING
IMPACT RESISTANCE
FORCE VARIATION
THUMP
CHIPPING
HYDROPLANING
PITCH
STONE RETENTION
NIBBLING
SLIP
CUSHIONING
CORNERING ABILITY
FIRST HARMONIC
RUNOUT
SIZE FACTOR
FLOTATION
LOPE
CONICITY
HIGH SPEED
SIPING
DEFLECTION
BURST
ZONE RESISTANCE
PRESSURE RISE
BUCKLING
SNOW AND ICE
PLUNGER
WHINE
INTEGRITY
FUEL ECONOMY
FATIGUE RESISTANCE
RUNNING TEMPERATURE
LATERAL PULL
Tire Performance RequirementsSTEER EFFECT
ROLLING RADIUS
STABILITY
FOOTPRINT
SQUEAL
TMPH
ROUGHNESS
ALIGNING TORQUE
MEAN GROUND /
CONTACT PRESSURE
PROFILE
LOAD CARRYING CAPACITY
VIBRATION ANALYSIS
ROAD HAZARD RESISTANCE
CHUNKING
FLATNESS
RUMBLE
HEAT GENERATION
SEPARATION
ASPECT RATIO
STOPPING ABILITY
STANDING WAVE
GROWTH
PUNCTURE RESISTANCE
RIM CHAFING
DRAG
HARSHNESS
FLEET DURABILITY
SUPPLENESS
CRACKING
JOINT SLAP
REVOLUTIONS/MILE
ENVELOPING
STIFFNESS
WOBBLE
RESPONSE
COOL RUNNING
BALANCE
MOISTURE RESISTANCE
WEATHER RESISTANCE
SHAKE
INFLATION PRESSURE
SPRING RATE
NONSKID
HOP
TREAD PRESSURE
BEAD DURABILITY
TORQUE
SLIP ANGLE
SKID RESISTANCE
EVEN WEAR
BEAD UNSEATING
CORNERING STIFFNESS
PITCH TONE
DIRECTIONAL CONTROL
DAMPING
POWER CONSUMPTION
Size Nomenclature
Passenger Light Truck
P225/60R16 LT235/85R16
Cross Section Radial Rim Dia Cross Section Radial Rim Dia
(MM) (Inches) (MM) (Inches)
Passenger *Aspect Ratio Light Truck *Aspect Ratio
Section Width
* Aspect Ratio = Section Height divided by Section Width
Lower Number = Shorter Sidewall & Wider Tread
Tire Construction
Radial
The benefits of using Radial
Technology:
•Outstanding traction due to
flat stable crown & larger
footprint
•Better distribution of
pressure in footprint
resulting in reduced soil
compaction & greater
flotation
•Reduced working time due
to less tire slip, greater
productivity
•Reduced fuel consumption
•Longer tread life
•Comfort & handling on the
road
The drawbacks of using Bias-Ply
Technology:
•In bias-ply tires the tread & sidewalls
share the same casing plies
•All sidewall flexing is transmitted to
the tread, resulting in:
•deformation in the tread contact
patch
•friction with the ground
•rapid wear
•reduced traction
•higher fuel consumption
Bias Ply
Tire Componentschapter
PARTS OF A TIRE
1 2 3 4 5
• Not all components are in
all tires.
Innerliner
Beadbundles
Beadfiller
Cord body
Sidewall
Shoulder inserts
Belt plies
Cap ply
Tread
CORE TIRE KNOWLEDGE
Innerliner
The innerliner is a rubber compound bonded to the inside of the cord body that retains air under pressure. It has no cord reinforcing and functions as an innertube in a tubeless tire.
CORE TIRE KNOWLEDGE
Tire Components
Tire ComponentsBead Bundles • Tire bead bundles are
large copper, brass, or bronze plated high tensile steel cords wound together. Tire beads occasionally include some type of fabric wrap to retain the bead shape prior to the curing process. The body plies of the tire are looped around the bead bundles to hold the plies in place. The bead holds the tire on the rim.
PARTS OF A TIRE
CORE TIRE KNOWLEDGE
Tire Components
• The bead filler is a
hard rubber
compound used to
provide stability to
the lower sidewall
and bead area.
Bead Filler
PARTS OF A TIRE
CORE TIRE KNOWLEDGE
Tire Components
• The cord body provides tire
strength and transmits
cornering forces from the
tread to the wheel. Rubber
coated cord, called body
plies, make up the cord
body. Body plies can be
polyester, rayon, or nylon.
Polyester is the most
common cord body.
The area of the body ply that
wraps around the bead is
called the turn up.
Cord Body [ tire casing ]
PARTS OF A TIRE
CORE TIRE KNOWLEDGE
Tire Components
• The sidewall is the area of a tire from the bead to the tread. It forms a protective covering for the cord body. Sidewall rubber compounds resist aging, cracking, cutting, and snagging, and contain sidewall treatments such as white lettering.
Sidewall
PARTS OF A TIRE
CORE TIRE KNOWLEDGE
Tire Components
• Belt plies are two or more
strong layers of cord under
the tread area. The main
function of the belt system is
to provide stability to the
tread area of the tire. They
assist in improving tire
mileage, impact resistance,
and traction by giving the
tread area extra strength and
stability. The most common
cord material used in the belt
plies is steel.
[ package or system ]Belt Plies
PARTS OF A TIRE
CORE TIRE KNOWLEDGE
Tire Components
• The cap ply also found in some tires is similar to belt edge strips only full width instead of just on the belt edges. These components may be used for a number of reasons, but most commonly to enhance high speed performance.
Cap Ply
PARTS OF A TIRE
CORE TIRE KNOWLEDGE
Tire Components
• The tread is the portion of the tire in contact with the road surface. The tread compound and shape are designed to optimize the wear, traction, handling, fuel economy, and cut resistance characteristics of the tire given the tire’s intended use.
Tread
PARTS OF A TIRE
CORE TIRE KNOWLEDGE
Tire Dimensions
• These are the basic
tire dimension
terms.
▪ Tread Width
▪ Section Width
▪ Section Height
▪ Overall Diameter
▪ Static Loaded Radius
▪ Aspect Ratio [profile or series]
TIRE AND RIM DIMENSIONS
CORE TIRE KNOWLEDGE
Tire Dimensions
• The tread width is the distance
from outer edge to outer edge of
the tread. You can estimate
differences between the existing
and the replacement tires by
comparing the tread widths. You
can estimate changes in fender
well and frame clearances by
dividing the tread width
differences between the existing
tire and the replacement tire by
two.
TIRE AND RIM DIMENSIONS
Tread Width
TREAD WIDTH
CORE TIRE KNOWLEDGE
Tire Dimensions
The section width is the width of a new tire when mounted on the tire’s measuring rim, including normal sidewalls but not including protective side ribs, bars, raised letters, or decorations. You can estimate the width differences between the existing and replacement tires by comparing the overall section widths. You can estimate changes in sidewall to fender well, frame, and suspension clearances by dividing the overall section width differences between the existing tire and the replacement tire by two.
TIRE AND RIM DIMENSIONS
Section Width
TREAD WIDTH
SECTION WIDTH
CORE TIRE KNOWLEDGE
Tire Dimensions
The section height of a new tire is the distance from the rim vertically to the highest point of the unloaded tread area.
TIRE AND RIM DIMENSIONS
Section Height
TREAD WIDTH
SECTION WIDTH
SECTION HEIGHT
CORE TIRE KNOWLEDGE
Tire Dimensions
The aspect ratio, also known as the profile or series, is the ratio of the section height to the section width. For example, a 75 series tire is approximately 75 as high as it is wide.
Lower aspect ratio tires, such as 60 series, generally offer performance advantages over higher aspect ratio tires, such as 70 or 75 series. They provide more responsive handling, more stability, and better high-speed capabilities.
TIRE AND RIM DIMENSIONS
Aspect Ratio [profile or series]75 SERIES
70 SERIES
Height
= 75% of Width
60 SERIES
CORE TIRE KNOWLEDGE
Tire Dimensions
• The overall diameter of a tire is
the distance from tread surface to
tread surface while inflated but not
loaded. It is twice the section height
plus the nominal rim diameter. You
can estimate the height difference
between the existing and
replacement tires by comparing the
overall tire diameters. You can
estimate changes in the tire to
fender well clearance and vehicle
ground clearance by comparing the
radiuses (diameter divided by 2 =
radius) of the two tires.
TIRE AND RIM DIMENSIONS
Overall Diameter
OVERALLDIAMETER
SECTIONHEIGHT
RIMDIAMETER
CORE TIRE KNOWLEDGE
Tire Dimensions
• The static loaded radius
is the distance from the
center of the axle to the
contact surface when a
prescribed load is applied
to a tire mounted on
the measuring rim and
inflated to the
recommended pressure.
TIRE AND RIM DIMENSIONS
Static Loaded Radius
OVERALLDIAMETER
RIMDIAMETER
SECTIONHEIGHT
STATIC LOADEDRADIUS
CORE TIRE KNOWLEDGE
How It All Works Together(Simplified Overview)
• The contained air pressure carries the
load
• The ply & belt reinforcement contain
the air pressure & transfer forces
between the tread & bead areas
• The tread provides traction
• The beads ‘lock’ the tire to the wheel
& transfer forces between them.
The Department of Transportation[DOT] Code is a serial number that denotes specific manufacturing information about the tire. The serial number includes the DOT label, the manufacturer and plant code, the tire size code, optional symbols from the manufacturer, and the date of manufacture.
The Department of Transportation [DOT] Code
CORE TIRE KNOWLEDGE
The last four digits should
be your concern! The first
two digits are the week that
the tire was produced and
the last two digits are the
year the tire was produced!
DOT XX XX XXX 5107
UTQGUniform Tire Quality Grading
Treadwear Grades
UTQG Treadwear Grades are based on actual road use in which the test tire is run in a
vehicle convoy along with standardized Course Monitoring Tires. The vehicle
repeatedly runs a prescribed 400-mile test loop in West Texas for a total of 7,200 miles.
The vehicle can have its alignment set, air pressure checked and tires rotated every 800
miles. The test tire's and the Monitoring Tire's wear are measured during and at the
conclusion of the test. The tire manufacturers then assign a Treadwear Grade based on
the observed wear rates. The Course Monitoring Tire is assigned a grade and the test tire
receives a grade indicating its relative treadwear:
100 would indicate that the tire tread would last as long as the test tire
200 would indicate the tread would last twice as long as the test tire
300 would indicate three times as long as the test tire
ETC.
Traction Grades
UTQG Traction Grades are based on the tire's straight line wet coefficient of traction as the tire
skids across the specified test surfaces. The UTQG traction test does not evaluate dry braking, dry
cornering, wet cornering, or high speed hydroplaning resistance.
The Traction Grade is determined by installing properly inflated test tires on the instrumented axle
of a "skid trailer." The skid trailer is pulled behind a truck at a constant 40 mph over wet asphalt
and wet concrete test surfaces. Its brakes are momentarily locked and the axle sensors measure the
tire's coefficient of friction (braking g forces) as it slides. Since this test evaluates a sliding tire at a
constant 40 mph, it places more emphasis on the tire's tread compound and less emphasis on its
tread design.
In 1997, the UTQG Traction Grades were revised to provide a new category of AA for the highest
performing tires in addition to the earlier A, B and C grades. Previously the A grade had been the
highest available and was awarded to tires that offered wet coefficients of traction above 0.47 g on
asphalt and 0.35 g on concrete. Today the grades and their traction coefficients are as follows:
Unfortunately the immediate value of this change to tire buyers will be limited. Use of the AA
grade will first be seen on new tires that are introduced after the standard was enacted and will then
appear later on tires that have had the required wet traction all along, but were introduced when the
single A was the highest available grade.
Traction Asphalt Concrete
Grades g force g force
AA Above 0.54 0.41
A Above 0.47 0.35
B Above 0.38 0.26
C Less Than 0.38 0.26
Temperature (Resistance) Grades
The UTQG Temperature Grade indicates the extent to which heat is generated/dissipated by a tire.
If the tire is unable to dissipate the heat effectively or if the tire is unable to resist the destructive
effects of heat buildup, its ability to run at high speeds is reduced. The grade is established by
measuring a loaded tire's ability to operate at high speeds without failure by running an inflated test
tire against a large diameter high-speed laboratory test wheel.
Every tire sold in the United States must be capable of earning a "C" rating which indicates the
ability to withstand 85 mph speeds. While there are numerous detail differences, this laboratory
test is similar in nature to those used to confirm a tire's speed ratings.
Unfortunately for all of the money spent to test, brand and label the tires sold in the United States,
the Uniform Tire Quality Grade Standards have not fully met their original goal of clearly
informing consumers about the capabilities of their tires. Maybe it's because tires are so complex
and their uses can be so varied, that the grades don't always reflect their actual performance in real
world use.
Temperature Speeds
Grades in mph
A Over 115
B Between 100 to 115
C Between 85 to 100
Load Index
Using a P195/60R15 87S tire size as our example, the 87S at the end of the size represents
the tire's service description. A service description identifies the tire's load index and speed
rating. Service Descriptions are required on all speed rated (except for Z-speed rated) tires
manufactured since 1991.
The first two digits (87S) represent the tire's load index and are followed by a single letter
(87S) identifying the tire's speed rating.
SPEED SYMBOLS
Speed Speed Speed
Symbol (km/h) (mph)
A1 5 3
A2 10 6
A3 15 9
A4 20 12
A5 25 16
A6 30 19
A8 40 25
B 50 31
C 60 37
D 65 40
E 70 43
F 80 50
G 90 56
J 100 62
K 110 68
L 120 75
M 130 81
N 140 87
P 150 94
Q 160 100
R 170 106
S 180 112
T 190 118
U 200 124
H 210 130
V 240 149
W 270 168
Y 300 186
When "ZR" appears in the size designation with the service
description, the maximum speed is as indicated by the service
description:
EXAMPLES
Tire Designation Maximum Speed
P275/40ZR17 93W 270 km/h (168 mph)
P275/40ZR17 93Y 300 km/h (186 mph)
For tires having a maximum speed capability above 149 mph, a
"ZR" may appear in the size designation. For tires having a
maximum speed capability above 186 mph, a "ZR" must appear
in the size designation. Consult the tire manufacturer for
maximum speed when there is no service description.
Tire Deflection
Vehicle Loading
&
Tire Inflation
This is IMPORTANT!
Can you tell inflation pressure by
sight?
Which has 15 psi and which 35 psi?
Were you able to distinguish
pressures?
Would you have noted this underinflation on your
car?
35psi15psi
What is Important to understand
and remember is…………..
• It all starts with air pressure
• Proper air pressure is the key to good tire
performance
• Proper air pressure is the key to good fuel
economy
• Every tire is designed to run at a specific %
deflection and air pressure is what controls the
% deflection
TIRE DEFLECTION
TIRES ARE DESIGNED TO
OPERATE AT A CERTAIN
% DEFLECTION
15 psi35 psi
OVERDEFLECTION
GENERATES HIGH STRESSES
AND HEAT BUILD-UP
•Reduced Handling
•Reduced Fuel Economy
•Fast/Irregular Wear
•Reduced Durability
~ 15 million cycles during
20,000 miles of tire life.
Tire Inflation• A tire’s maximum load and inflation pressure is shown on the
sidewall
• A tires proper inflation pressure (for a
specific vehicle application) is that
recommended by the vehicle
manufacturer as shown on the vehicle
placard or in the owner’s manual
• Underinflation is the leading cause of tire failure and may result in
excessive heat buildup, component separation or “blowout”
• Maintaining proper inflation pressure is the single most important
thing you can do to ensure tire durability and maximum tread life.
• Overinflation increases stiffness, which may deteriorate ride,
generate unwanted vibration, increase the chances of impact
damage and result in fast / irregular wear.
Air Pressure Effects
On Tires
Pressure Effects on Fuel Economy
10
12
14
16
18
20
22
7 15 23 30 37 44
Inflation Pressure (psi)
Fu
el E
co
no
my (
mp
g)
i
Note: Large Sedan or Minivan; P225/60R16
• Overinflation helps very little.
• Underinflation hurts a lot!
Design Pressure
0
20
40
60
80
100
Proper Inflation -5 psi -10 psiPerc
en
tag
e o
f T
ire W
ear
Lif
e
'
Pressure Effects on Tire Wear Performance
• Slight underinflation can have a significant affect!
Design Pressure
But There is a Free Lunch!
• Proper inflation pressure (or lack thereof) can have a
very significant effect on rolling resistance.
60
70
80
90
100
110
120
26 29 32 35 38 41 44
Inflation Pressure (psi)
Ro
llin
g R
es
ista
nc
e (
rati
ng
) '
Design Pressure
Lower is Better
Yeah, But . . .Doesn’t the TREAD Act require Tire
Pressure Monitoring Systems (TPMS) in
cars starting in 2005 (100% by Sept, 2007)
and won’t that handle this low inflation issue?
Unfortunately, the TPMS dictated by the TREAD Act is only required to notify the driver if the pressure drops by 25% (or approximately 8 psi for typical car applications). TPMS is not a remedy for poor tire inflation maintenance.
Trash
Indirect TPMS relies on cars' anti-
lock braking system (ABS). Since tire
inflation levels affect tire rotation,
indirect TPMS relies on the
differences in wheel rotation to detect
under-inflation. Unfortunately,
indirect TPMS cannot detect all four
tires being under-inflated and is prone
to false alarms, for example when a
long curve in the road causes the
outside wheels to rotate more than the
inside wheels.
Direct TPMS is applied to all new
cars and installs a monitor directly in
the valve of each tire and lights up a
dashboard alert when the tire pressure
is 25% or more below the
recommended level.
Two types of TPMS Systems.
The TPMS system does not
mean that you do not have to
check air pressure!
So Maintain Your Air Pressure!
• Most light vehicle tires can lose about 1 psi
per month through leakage through the
sidewall or around the bead/valve.
• Tire pressures will drop about 1 psi for every
10°F ambient temperature drop.
• It won’t take long to undo all the rolling
resistance improvement the tire engineer
worked so hard to put in.
• Check your tire pressures monthly. It’s the
FREE LUNCH!
Nitrogen:
• Reduced wheel corrosion
• Prevents inner rubber
deterioration by oxidation
• Tires run cooler
• Cost Money
• What % N2 are you paying for?
Nitrogen vs Air
NitrogenAir
Run-Flat Technology
Run-flat tires offer drivers temporary extended mobility even after a puncture allows complete air pressure loss.
However, even run-flat tires will fail if driven too fast, too far or too heavily loaded when flat.
Note that a run-flat tire's endurance is dependent on operating conditions such as the flat tire's position on the
vehicle, vehicle load, ambient temperature, driving speed and distance traveled. Run-flat tires cannot be driven faster
then 50 miles per hour and typically offer up to 50 miles of extended mobility. Selected applications, based on vehicle
and the run-flat tire design can range from just 25 miles up to 200 miles. Consult your vehicle owner's manual to
determine what you should expect.
Runflat Technology
Pros:
• You can drive on a flat tire:
.
• Better stability after a blowout:
• Lower vehicle weight:
Cons:
• No spare:
• Reduced tread wear:
.
• Blowouts are still possible:
• Hard to tell if it is low on air:
• Harsher ride:
Cost:
• Less on-shelf availability:
Runflat Technology – Pros and Cons
Runflat Technology
Self-Sealing Tires - Self-sealing tires are designed to fix
most tread-area punctures instantly and permanently.
There are three main types of “Run-Flat” Technology:
• Self-Sealing Tires
• Auxiliary Support Systems
• Self Supporting Tires
Auxiliary Support Systems- Auxiliary supported systems
combine unique wheels and tires used for Original
Equipment vehicle applications.
The International Organization for Standardization (ISO), a
worldwide federation of national standards bodies, has adopted
a run-flat system symbol for extended mobility systems
featuring an internal support ring.
Self Supporting Tires - Self-supporting tires feature a stiffer
internal construction, which is capable of temporarily
carrying the weight of the vehicle, even after the tire has lost
all air pressure.
The International Organization for Standardization (ISO), a
worldwide federation of national standards bodies, has adopted
a run-flat system symbol for extended mobility systems
featuring self-supporting run-flat tires.
Airless tire technology features a unique spoke structure designed to support the weight of a vehicle, effectively
eliminating the need to periodically refill the tires with air.
Benefits of Airless Tires for Cars
No flat tires – ever
You won’t need a spare tire
Vehicle-heavy industries can save money
Airless Technology
Tire Mounting
Rim Diameter Trend - O.E. Fitment
TrendO.E. drives the trend
Source: Global Insight Aug. 2007 Source: RMA Forecast Feb. 2008
2%
7%
16%
20%
31%
33%
35%
39%
31%
30%
19%
19%
12%
0% 20% 40% 60% 80% 100%
2010
2007
2004
13-14" 15" 16" 17" 18"& Larger
15” 17”
18”
Tire Mounting• Proper Mounting &
Dismounting General
Information: Tire changing can be
dangerous & should only be
performed by trained personnel.
• Never strike the tire or rim with a
hammer!!
• Use proper tire mounting tools &
equipment.
• Consult RMA mounting guidelines
and safety precautions
Tire Mounting
• Always work on a clean surface.
• To facilitate mounting and dismounting, lubricate
rim & tire beads with proper lubricant.
• Never use petroleum-based or silicone lubricants.
• Excessive lubricant can cause rim slip.
• Inflation & Proper Bead Seating NEVER
INFLATE AN PSR TIRE OVER MAX.
INFLATION PRESSURE TO SEAT BEADS!!
Bead Distortion & Damage from Mis-mounting
Tire Mounting
• Causes Of Mounting Damages During removal, use of sharp tools or
hammer to unseat beads.
• During mounting, cutting or tearing of bead against rim flange,
most often due to inadequate lubrication (during mounting of first
bead).
• During mounting: cut caused by sharp or off-center roller (typical
OE mounting damage).
• During mounting: cuts can be caused by sharp or damaged rim
flange, often when bead is forced with a hammer (during mounting
of second bead).
Tire Application Guidelines
New Tire Application Guidelines
• When you select a pair of replacement tires of the same
size and construction as those on the vehicle, we
recommend you place them on the rear axle
• A single new tire should be paired on the rear axle with
the tire having the most tread of the other three
2 Tire Application (Wet Conditions)
1. Same tires all around, same amount of wear:
1. Traction equal on all tires.
2. Neutral steer.
2. New tires on the front:
1. Front traction greater than rear traction.
2. Front end holds; rear end lets go.
3. Oversteer
3. New tires on the rear:
1. Rear traction greater than front traction
2. Rear end holds; front may tend to let go.
3. Understeer
Neutral steer
Oversteer
Understeer
4WD and AWD Guidelines
Always check and follow the recommendation in the vehicle
owner’s manual, even small variances in outside diameter may cause
drive-train damage or mechanical malfunction. If no instructions for
tire mixing appear in the vehicle owner’s manual follow these
guidelines:
• Do not mix sizes.
• Do not mix radial and bias-ply constructions.
• Do not mix tread patterns such as all-season and all-terrain.
Winter Tire Guidelines
• It is recommended that snow tires be applied to all four
wheel positions
• If winter tires are installed on the front axle of any vehicle,
they must also be installed on the rear axle
• If studded tires are installed, they must be applied to all four
wheel positions.
• Never apply non-radial snow tires on the rear axle if radial
tires are on the front axle unless the vehicle is equipped with
duals on the rear axle.
Seasonal Tire Application Guidelines
Police Pursuit TiresWinter TiresEverything Tires
Top Speed…9 MPH!!!
Hybrid and Electric Vehicle Tires
Nissan Leaf
Tire Rotation Recommendations
Tire rotation is extremely important to achieve even treadwear and
maximum tire mileage. Refer to the vehicle's owner’s manual for
rotation intervals and rotation pattern recommendations. If no
rotation period and/or rotation pattern is specified, tires should be
rotated approximately every 5,000 miles.
Tirerack.com
Tire Maintenance
Suggested Maintenance Policy
• Inflation is to be checked in all (4) tires at the
beginning of each shift (before you get in the
vehicle for the first time - as close to ambient
temperature as possible)
– use an accurate pressure gage
– never bleed air from a tire which
has been properly inflated previously
– make sure a quality metal or plastic
valve cap is is place
• Complete a vehicle ‘walk-around’ every time you are preparing to
re-enter and operate the vehicle - visually inspect each tire
– look for changes in deflection
– look for cuts, cracks, punctures, abrasions, bulges, etc.
• If you suspect a tire problem, have it inspected by a professional
Tire Repair
Can Tires Be Repaired Properly?
• Complete details can be found on the web
– RMA (Rubber Manufacture’s Association)
– TIA (Tire Industry Association)
– Or contact your tire vendor’s technical service
representative
Tire Manufacturer's Puncture Repair Recommendations
Manufacturer/Brand Speed Rating Multiple Repair Locations
BF Goodrich* Maintained 3 repairs, minimum 90° apart*
Bridgestone** Voided Repairs cannot overlap
Continental*** Voided Repairs cannot overlap
Dick Cepek/Cooper** Voided Repairs cannot overlap
Dunlop**** Maintained Repairs cannot overlap
1 repair, H and above
Firestone** Voided Repairs cannot overlap
Fuzion** Voided Repairs cannot overlap
General*** Voided Repairs cannot overlap
Goodyear**** Maintained Repairs cannot overlap
1 repair, H and above
Hankook** Voided Repairs cannot overlap
Kumho** Voided Repairs cannot overlap
Michelin* Maintained 3 repairs, minimum 90° apart*
Pirelli V and Above Repair Not Endorsed by Pirelli
H and Below Maintained 2 repairs, minimum 180° apart*
Toyo* V and Above Reduced to H Repairs cannot overlap
H and Below Maintained Repairs cannot overlap
Sumitomo** Voided Repairs cannot overlap
Uniroyal* Maintained 3 repairs, minimum 90° apart*
Yokohama** Voided Repairs cannot overlap*Only 1 repair permitted for run-flat tires**To be driven as non-speed rated (85 mph/137 kmh maximum)***Voids materials, workmanship and tread wear-out warranties****Only 1 repair permitted to retain H and above speed ratings.Note: Tire Rack will not repair any speed-rated run-flat tires because we cannot confirm their internal structural integrity.
Tire Repair
Run Flat-Rubber Dust
When you see rubber dust that has accumulated in the interior of a tire, at some time, that
tire was operated with insufficient air pressure for the load that it was caring. Any tire
with that type of damage will need to be replaced.
Tire Aging
The NHTSA report concluded that there was no need to add an aging requirement to Federal Motor Vehicle Safety
Standard (FMVSS) No. 139 because the current standard has made passenger tires more robust, crash data shows that
tires are performing better, and tire pressure monitoring systems (TPMS) are alerting drivers of under inflation.
Since service and storage conditions vary widely, accurately predicting the actual serviceable life of any specific tire
based on simple calendar age is not possible.
Replace Old Tires Even if There is Tread Remaining
• Vehicle Manufacturers Recommend Replacement at 6 Years
• Tire Manufacturers' Warranties Expire at 6 Years
• Tire Manufacturers Recommend Replacement at 10 Years
• Industry Experts Recommend Replacement at 10 Years
Certain chemicals added to new tires allow rubber to be soft
and flexible. Over time and as air migrates through the tire, the
chemical's effectiveness weakens, allowing rubber to become
more brittle and lose strength.
Vehicle Door Placard
Door Placard
Cold tire
pressure
Gross, front and rear vehicle weights
Original
equipment
tire size
(including
spare)
Tire rim size
P-Metric vs Euro-Metric
vs Light Truck
P-Metric vs Euro-Metric
Standards Institutions
1. "P" in front of the tire’s dimensions indicates that the tire manufacturer
designed it under the American "P-metric" tire standards set by the Tire
and Rim Association (TRA).
2. Absence of the "P" (or other letters) means it meets the standards of the
European Tyre and Rim Technical Organisation --- the "European metric"
system (ETRTO).
Load Index
P195/70R14 has a load index of 90 (Max 1,323 lbs)
195/70R14 has a load index of 91 (Max 1,356 lbs)
Tire and Rim Association Designations
"P" is for passenger vehicles.
"LT" is for light truck vehicles.
"ST" is for special trailer.
"T" is for temporary.
P-Metric vs Light Truck
Many 1/4-ton and 1/2-ton vehicles use Euro-metric and P-metric sized tires, while 3/4-ton and 1-ton
vehicles use LT-metric sized tires.
Euro-metric and P-metric tire sizes were originally designed for cars and station wagons, however they
have also been used for light truck applications because most vans, pickup trucks and SUVs are used to
carry passengers, not cargo. Most of the new light trucks being produced today are equipped with Euro-
or P-metric sized tires because they offer lighter weight, lower rolling resistance and less aggressive tread
designs (which makes them better riding, more fuel efficient and less noisy) than typical heavy-duty tires.
Tire size
P265/70R17 113S
2535lbs
Tire size
LT265/70R17
121/118 E
3197lbs/2910lbs
P-Metric vs Light Truck
However there is an idiosyncrasy governing the use of Euro-metric and P-metric sized tires on vans,
pickup trucks and SUVs because these vehicles have a higher center of gravity and greater probability of
being overloaded than passenger cars. In order to accommodate this, vehicle engineers are required to
specify Euro- or P-metric sized tires rated to carry 10% more weight than would be required if they were
used on a passenger car. This is the equivalent of taking the tire's load capacity branded on its sidewall
and multiplying it by 91%. For example, a Euro- or P-metric tire designated to carry 2,000 pounds on a
car is restricted to carrying 1,820 pounds when used on a van, pickup truck or SUV.
On the other hand, LT-metric sized tires were specifically developed for use on light trucks and provide
the full tire load capacity branded on their sidewall. They are the little brothers of the heavy-duty tires
fitted to 18-wheelers and busses, and use the same basic engineering guidelines regarding load capacity.
Because of this, LT-metric sized tires are built very strong, and use higher inflation pressures to carry a
given load in order to provide the desired safety margin. You really don't want the tires of the 18-wheeler
along side you on the Interstate running at the limit of their endurance, do you?
Tire size
LT265/70R17 121/118R E
3197lbs/2910lbs
Tire size
P265/70R17 113S
2535lbs
Accident Scenario
Accident Scenario
Accident scenario #1
Late model sports car impact guardrail
Rainy day
New tires on the front axle, rear axle half worn tires
Accident Scenario
Accident scenario #2
Late model SUV
Sunshinny day
Just purchased a set of four used tires
Accident Scenario
Accident scenario #3
Late model Pickup (sandbags in bed for traction)
Very cold day
Just purchased new allseason tires
“Out of Service”
Conditions
Questions?
Thank You !
