Download pdf - Entretien RS boxxer

MB

ATEC

H

Lower fork service for air-sprung sliders

88 www.mbaction.com

O ut of the box or off the showroom floor, your bikewill ride fine, but it will not have optimized suspen-sion performance. Dedicated downhillers are known

for meticulously tuning their suspension and always lookingfor performance advantages that come through regularly ser-vicing their forks. Also, well-serviced and clean suspensioncomponents simply last longer.

We’ve chosen the popular 2010 RockShox Boxxer WorldCup and will take you step-by-step through a few basic main-tenance tips that will unlock improved fork performance.Although we’re working on a downhill fork, the lower legremoval, seal servicing and lower leg installation steps willapply to most RockShox Solo Air trailbike forks, like theLyrik and Revelation, for example.

Before working on your own suspension, we recommendchecking out the tuning guide for your fork that can befound on RockShox’s website. This guide is easy to under-stand and is a good starting point for helping wrap your headaround what the moving parts inside your slider are up towhen you’re bombing a trail.

Unlocking RockShoxFork Secrets

Tools you’ll need

Servicing your fork requires a variety of

basic tools, such as a 5-millimeter hex

wrench, 12-millimeter socket, 24-milli-

meter flat wrench, rubber gloves, isopropyl

alcohol, shop rags, oil bucket, bike stand,

plastic mallet, awl or sharp pick, flathead

screwdriver, downhill tire lever, wood or

plastic dowel, grease, fork oil and a ruler.

After you’ve removedthe fork from your bikeand have placed thefork in the bike stand,use a pick and a flat-bladed screwdriver toremove the retainingclip. Be sure to placea bucket below thefork to catch the oldfork oil.

1

Remove the beginning and ending stroke rebound adjusters anduse a 24-millimeter flat wrench or crescent wrench to loosen andremove the rebound shaft bolt. Remove the crush washer andretainer from the bottom of the bolt, and then reinstall the shaftbolt a few turns. Take note of how the rebound assembly comesapart to make reinstallation easier later on.

2

3

Place a 12-millimeter socket over the rebound adjuster shaft andagainst the rebound bolt. Use a rubber mallet and firmly strikethe socket to free the rebound shaft from its press-fit inside thelower leg.

Speed and style: Specialized’sBrendan Fairclough is on the shortlist of World Cup racers who havestyle at full speed. In this photo,Brendan and his RockShox BoxxerWorld Cup launch the GLC drop inthe Whistler Mountain Bike Park.

www.storemags.com & www.fantamag.com

7

6

5 8

4

Once the press-fit isbroken, remove therebound adjustercompletely fromthe bottom of thefork leg.

Use a 5-millimeter hex wrench to loosen the spring shaft bolt,and back it out four turns. Use a rubber mallet to strike the shaftbolt and break it free from its press-fit in the lower leg. Removethe shaft bolt completely.

March 2010 / MOUNTAIN BIKE ACTION 89

Position the forkupside-down in thestand and allow theoil to drain into thebucket. At first, verylittle oil flowed for us,but after threeattempts to break therebound and shaftbolts free from thepress fit, all of the oildrained into the pan.

Remove the lower leg from the fork by pulling out each uppertube. Spray the fork legs with isopropyl alcohol and wipe downwith a clean, lint-free rag. Allow any remaining oil to drain intothe bucket. This is a good time to inspect the upper tubes fordamage. Scratches can lead to oil leaks and allow debris to con-taminate the fork internals.

Use a “spoon-shaped” tire lever or a large flat head screwdriverto pry underneath the lip of the gray seal. Stabilize the fork legand use a downward force to remove both seals at this time.


90 www.mbaction.com

MB

ATEC

H

9

11

10

INSIDER TIPS

John Canepa is Eric Carter’s per-sonal wrench and a factory mechan-ic for GT Bicycles. John knows theins-and-outs of the RockShoxBoxxer and has given us some ofhis personal tuning tips for a butterysmooth fork.

Lubing the seals: The grease ofchoice is Liquid-O-Ring PM600Military Grease. It is smoother thananything else I’ve tried. Better thanPhil Wood, Park or anything elseusually found in bike shops. It is redand comes in a cylindrical tube. Ihave found it at select auto partsstores, but not everyone carries it.Apply a healthy dose of grease toboth the inner and outer seals. Dothis before lubing the bushings inthe lowers.

Lubing the lower legs/bushings:Do this after applying grease to the

GT’S FACTORY WRENCH

seals. The reason is that grease willstay in place, whereas oil will get allover the place if not handledcorrectly. Hold the lowers ina horizontal position andsquirt about 20cc of lubeinside. Be careful to keepthe lowers steady, or the oilwill drip out the bottomholes, use a 50/50 mix of3wt or 5wt shock oil withRockShox Red Rum. Thetrick to making sure thebushings have full oil cover-age is to rotate the legs in a360-degree motion whilekeeping horizontal at thesame time. You can lookinside the lowers while doingthis and actually see the oilcover the bushings. Thebrand of shock oil I use is

Spray isopropyl alcohol inside the fork lowers, and use a cleanrag and a dowel to wipe the inside of the fork clean. Do this acouple of times on each side.

After we cleaned thefork seals, we used our

homemade seal installationtool, which is simply a pieceof 1-1/4-inch PVC pipe tofirmly press in the seals. Wipedown the outside of the sealwith isopropyl alcohol andinstall them dry. Do not usegrease for the seal installation.

Apply liberal amounts of waterproof grease to the dustwiper and oil seal.

Factory GT mechanic John Canepa (left) helped usout with some of his tuning tips for the RockShoxBoxxer World Cup. Here he tweaks a bike setup withEric Carter at Mammoth Mountain.

Maxima, commonly found at mostmotorcycle shops. I prefer 3wt, but5wt is acceptable.


13

12

14

Gently slide the upper leg assem-bly into the fork lowers. Be sure toinstall the legs in the proper sidefor the fork. Slide the legs in untilyou feel the spring and dampershafts make contact with theinside of the legs, and then pullthe upper tubes back out a fewinches to make room for oil andlubrication. Place the fork back inthe stand and carefully clamp thefork lowers in at about a 45-degree angle. This allows lubrica-tion to coat the inside of the forklowers and bushings.

Measure 20cc of a 50/50 mixture of 15wt fork oil and RockShoxRed Rum lubricant and inject the mixture inside each fork leg.RockShox says 15wt oil sticks to the bushings better than lighterweight oil, but we know of race teams that run 3wt or 5wt oil intheir Boxxers. The lighter-weight oil is said to make the fork moresensitive and active, but requires more frequent servicing.

Rotate the fork 360-degrees a few times so the oil coats thebushings inside the fork.

Slowly slide each upper tube completely into the lower leg untilthe shaft threads are visible through the shaft holes. Be careful,and slide the legs slowly, because sliding them too quickly willcause oil to shoot out of the shaft bolt holes. Check for oil on theshaft threads, and use the corner of a clean rag to dry thethreads if necessary.

15


MB

ATEC

H

Thread the rebound damper and spring shaft bolts into thethreaded shaft ends. Use the 5-millimeter hex wrench andcrescent wrench to properly tighten the bolts.

16

17

18

Install the ending stroke rebound knob, washer, and beginningstroke rebound knob on the rebound adjuster shaft.

Lightly push down on the rebound adjusters to access theretaining clip groove. Place the retaining clip into the groove andpush it into place with a small flat-head screwdriver. Wipe downthe entire fork with isopropyl alcohol and reinstall the fork onyour bike. Voila! Your fork lowers and seal service is complete. ❏
