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derailures are driving me nuts!(6 posts)

derailures are driving me nuts!Duane Gran
May 24, 2001 6:06 AM
Okay, as many of you know I ride a lot, but I'll confess that I'm not much of a wrench, but I'm learning. I'm hoping someone can steer me in the right direction on a little problem I'm having.

Recently I acquired a second frame. My main steed is a Trek 5200 with Ultegra. Having crashed several times my Ultegra group was pretty scraped up, so I ordered a Dura Ace group. I put the Ultegra onto my Giant and put the Dura Ace onto the Trek. Actually, the LBS mechanic did this job for me, but I watched observantly and even helped a little.

So here is the problem... I have these Rolf wheels with my Ultegra cassette (12-25) on them. No matter what I do I can't get the shifting to be nice and smooth like it used to be when I had just one bike. It is working fairly well on the Trek, but the chain-rub on the Giant is loud enough to wake the dead. I have consulted "Zinn and the art of roadbike repair" for ways to adjust the front and rear derailure's, but it only helps a little. I'm going to have the shop help me some more with this.

The real crux of the problem is that I have to spend a half an hour fiddling with the derailures whenever I switch between my Zipp race wheels and my training Rolf wheels. Even at that, I am not able to acheive the buttery smooth shifting I had previously. I'm sure in time I'll get better at it, but is this common? Am I being unrealistic in my desire to just throw a wheel onto the bike and ride?

At my request, the shop inspected the cassette and made sure that I didn't have excessive wear. I have heard that you should buy a new cassette with a new chain, but I think my problem is in derailure adjustment, but I just can't get it right. Unfortunately, a forum like this isn't a good medium for explaining how to adjust a derailure, so I'm mostly interested to know if others have faced frustration using two wheelsets and how you may have resolved it.
Could be....muncher
May 24, 2001 8:14 AM
That the spacing is slightly different on the two wheels, i.e. the block is not the exact same distance from the derail mount on both - hence the need to adjust. Have both had the same wear? If one is newer and you have not replaced the chain - that could be the problem, though of course you may find that the older block still does not shift totally smoothly with the new chain (depends on amount of wear). Are they both the same series blocks (HG or whatever) if not the different teeth profile could lead to shifting probs, esp if you don't have a chain that is compatible with both?

When you say "chain rub" what do you mean exactly - where is the rub, or do you mean that it's noisy running over the block (if the latter - incompatible chain/block wear is the culprit)

In any event, in my experience, you will be very lucky to swap wheels and need no adjustment at all, unless you have exactly the same hubs and set-up on both - you generally have to tweak the adjuster a little to get it spot on, it's just the way the world is.

Annoying though, isn't it? Hope you get a fix...
re: derailures are driving me nuts!nodima
May 24, 2001 9:42 AM
If I understand correctly, your old Derailleur is on the Giant, and the new one is on the Trek. It works when you have the wheels on the Trek, but not the Giant. Could it be that the Derailleur hanger or derailleur itself is bent?

Get the derailleur hanger checkedJamesT.Kirk
May 24, 2001 1:14 PM
I had a slightly bent hanger on my frame that was wreaking havoc on my Daytona 10 group. Had the shop check it out, they straightened it and now it's flawless.

I'd say this would be a good place to start given your statements about crashing and scraped up derailleurs......
re: derailures are driving me nuts!tkohn
May 24, 2001 8:49 PM
Chances are that the cassette is in a slighly different position from wheel to wheel. Your LBS should be able to add a very thin round shim behind one of the cassettes on the freehub body to help make things a little more consistant. Good luck.
Thanks for the suggestionsDuane Gran
May 25, 2001 12:03 PM
I will be taking your suggestions to my LBS. I appreciate it and if I come to some good resolution I'll be sure to share the info.