|   RockShox Judy TT Innards - Long Newbie Question | OldGuy
Dec 21, 2001 8:28 PM | | Sorry for the long posting...
My LBS just replaced a broken Jett with a 2001 Judy TT. The Judy seemed very stiff, and not nearly as responsive as the Jett. I popped the spring out and stroked the fork through its travel, and noticed that it seemed to be binding in the first inch of travel, then freed up and moved smoothly for the rest. I then removed the lowers to see what was binding, and discovered a 1 1/2" long, slightly tapered round rubber bumper that the compression rod slides through in each lower fork leg. I am assuming that these bumpers are the infamous MCU dampers. Anyway, these bumpers didn't slide smoothly over the compression rods in the first inch or so of travel, so I assumed this to be the problem. I reassembled the forks, but left the rubber bumpers out. Voila! The forks now slide much easier, without the initial binding. My question is, is it dangerous to ride the bike without the rubber bumpers in the forks? It feels like there is no damping, which is OK for now (upgrading as soon as I can afford it!!!). Will I damage the fork? What would happen if I smoothed the bottoms of the compression rods with sandpaper, allowing the bumpers to slide more easily?
Next question, in looking at the exploded view on the RockShox website, it appears the bumpers (MCU units) are supposed to go between the bottom of the spring and the top of the compression rod. They were actually in the lower leg assembly, below the stanchions, and appear to function sort of like bottom-out bumpers. Is my fork assembled wrong, or is the RS exploded view out to lunch?
Thanks for any advice, and sorry for all the questions!
Steve |
| medium long answer. | heff®
Dec 21, 2001 9:09 PM | | The black bumpers you took out of your lowers are the bottom out bumpers. They're not supposed to slide, they're supposed to sit at the bottom of the rods, and keep the stanchions from smacking into the lowers. Put them back on.
MCU's are inside the stanchions, part of the spring stack. They rest on top of the spring. The bumper you're seeing in the diagram is the topout bumper, which keeps the fork from extending so much that the compression rod bangs into the bottom of the stanchion. Leave that in as well.
Your fork feels like it has no damping, because it doesn't. It's a simple spring stack fork, not any different from your Jett, really. The bottom out bumpers have nothing to do with how the fork responds.
heff® |
| Hmmmmm... | OldGuy
Dec 21, 2001 9:35 PM | | OK, I get the bottom-out bumper idea. I was kind of wondering about that when I was looking at the innards - they are under the stanchions and wrap around the compression rods, which don't move relative to the lowers. But why would removing them cause the fork to slide better? Is it one of those take-it-apart-and-put-it-back-together-again-and-it-works-right-now things? I'll put 'em back and see what happens.
Also, my fork, from top to bottom, has: cap with preload adjuster, coil spring, compression rod with top-out spring ass'y, stanchions, bottom-out bumpers, lowers, and compression rod bottom bolts. I can't see any MCU in the coil spring area, either above or below the spring... More Hmmmm.....
Steve |
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