04-10-2012, 03:47 PM
Joined: Nov 2008
Location: San Jose, CA
Replacing shock spring
If you’re thinking of installing a heavier shock spring rather than replacing the entire shock, here’s my experience.
I weigh 235lbs wearing street clothing, don’t know how much more my riding gear weighs but it’s the usual amount. I always carry 20-25lbs of miscellaneous stuff in the tailbag or saddlebags. My bike is a single-seater, I’ve removed the passenger pegs; at 6’2”, there’s no room for a passenger. Riding is 20% freeway, 75% “spirited riding” on paved and sometimes rough mountain roads, 5% dirt forest roads.
I had the OEM shock spring adjusting collars all the way down, and was happy with the ride. But, I couldn’t carry camping gear, the spring compression was maxed out. So I bought ProCycle’s heavier spring of the two offered. Now, fully loaded with camping gear, the ride is plush and there’s still 1.25” of thread left under the adjusting collars. Rebound dampening is set at 3 full rotations counterclockwise; the spring does not overwhelm the dampener for my usage.
I had read different ways of doing the job: taking the shock off from the top or the bottom, or just dropping the spring off the bottom. I did what appeared to me to be the easiest way, leaving the shock in the bike, dropping off the spring. My main concern was how to take the pressure off the linkage when removing the bolts. Here’s what I did.
Back off adjusting collars to near top of shock using a hammer and a drift – will take a few minutes of easy work.
Raise bike on lift; lifting arms under motor.
Lift bike far enough to put 8” support under rear wheel; I used four pavers I had laying around; you could get by with less support, though I don’t know how much less.
Lower bike until the bike’s weight begins to come off the lift; the rear wheel will then be raised as close to the fender as it will go.
Tie down bike to lift.
Remove dogbones – be careful not to cause inner tubes/races to fall out.
Remove bottom shock bolt.
Remove “Y” bracket – be careful not to cause inner tubes/races to fall out.
Push up thick U-shaped piece at bottom of shock until it clears the bottom of the shock and can be pulled off shock; may have to first push rubber conical bumper up on shock shaft – high friction.
Spring and a couple other parts drop off bottom of shock shaft.
Take the parts containing bearings to your workbench, carefully push out the inner race/tube, lube the needle bearings (mine all had a light coating of OEM grease), carefully reinstall the inner race/tube.
Reinstallation is reverse of the above, taking care not to push out the inner race/tube when inserting the bolts. I adjusted the lift height minutely to get the bolt holes to line up.
Dogbone bolt nut torque is 72.5lb-ft or 100N-m.
The front nut on the “Y” piece is 58.0lb-ft or 80N-m, however there’s no way you can get a torque wrench on that nut.
Shock bolt torque is recommended at 37N-m by Rick at Cogent Dynamics, using medium strength threadlocker (blue Loctite); the spec in the manual is WRONG and may result in stripped threads.
Overall, an easy operation.
The older I get, the better I was.