jockey wheels question
 

Hi folks,
This is my first foray in to the mechanics forum.

I roll with friction shifters, I recently installed a new driveline, I replaced the crankset (wound up haveing to adjust the outboard (high range) screw on the front derailleur, in order to get the chain to go on the large ring. The rear derailleur adjustment is fine). I also replaced the chain and cassette.

Since I replaced the drive line I have been having issues that I didn't have before. The chain keeps skipping/hitching randomly, more so under load. Sometimes it feels like the bike is shifting itself (although I don't think that it actually is).

I noticed today that my jockey wheels look awful pointy compared to the jockey wheels on the other bikes that I have.

Is there anything specific that I need to know, or be aware of, in order to replace them with ones from one of my other bikes?



I didn't replace the jockey wheels, I'm thinking that permaybehaps I should have changed them too.

What bike, how many rings up front, what is the current chainline? What new components did you install (make and model)? Are the shifters friction adjustments tight enough as to not allow the new derailleur to pull cable tension and shift or try to shift on it's own? The old shifters may be too weak for the new rear derailler.

I only installed a new crankset (3 rings, OEM replacement part, Shimano 42-24t), chain, and cassette (Shimano 11-34t 8speed). I did not change the derailleurs.
That is why I thought maybe I might need to replace the jockey wheels. This is the 2nd or 3rd time I have replaced the crankset, chain and cassette, since the bike was new in 2008,. The other times (using the same components as listed above) I did not have the issues that I am having now.
I don't really think that it is actually ghost shifting.

I think that I have a wider Q-factor now, I have no idea about the chainline. The bike is a 2008 Kona Fire Mountain/Xtracycle.

Since your running in friction mode, and I assume you're used to trimming it properly, I doubt it's any of the issues related to index shifting.

Also, since the chain and all the sprockets were replaced we can eliminate the typical chain/sprocket wear mis-match problems.

Also the jockey wheel didn't suddenly get worse when you made the change, so unless you were having shift problems before, we can rule that out, though replacing it won't hurt.

That narrows the possibilities down to not many. I suspect that either the chain length changed or one of the sprockets isn't the same size, and the RD is sitting either too close (more likely) or too far from the cassette causing interference between the cassette and jockey wheel. They jockey must lead the chain onto the sprockets, and to do so must be forward (along the chain) by about an inch or so. Adjust the "B" screw (back of upper body) to set the height of the RD to be close but never too close to each sprocket, especially the larger ones where the clearance will be closest.

I will add my $.02: it could be a stiff link in the chain, especially at the link with the new pin. Detention the chain by taking it off the chainring and ensure all links are free to flop around.

Good point, but there's an easier way to check for stiff links. shift into a middle gear where chain (sprocket) alignment is good.

Push the idler pulley forward so the lower loop sags forming a catenary. Backpedal slowly and watch as the chain emerges from the pulley. Look for any link(s) that doesn't immediately open into the same curve as it's neighbors.