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Difficulty with front and rear shifting

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Difficulty with front and rear shifting

Old 05-22-16, 12:03 AM
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bhdavis1978
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Difficulty with front and rear shifting

Hi all,

I'm having some difficulty with the shifting on my bike on both the front and rear derailleur. I can't get the shifting dialled in on the rear derailleur with the barrel adjuster. I can either get pretty good shifting on the low end of the cassette or the high end of the cassette but not both. For example, if I get the shifting dialled in on the low end of the cassette then it shifting from the 23t cog to the 25 takes doesn't happen smoothly. Plus down shifting back to the 23 is unreliable. Sometimes downshifting doesn't do anything, other times it does but then when observing the chain on the cog it looks like the chain keeps trying to move back up. The only way to reliably stay on the 23t cog is to down shift to the 21 and then back up to the 23. Additionally the whole system is very sensitive at this point, slightly adjusting the barrel adjuster a little bit one way or the other noticeably degrades shifting performance more so than I have ever noticed on other bikes with minor barrel adjustments (e.g. 1/4 turn).

On top of that, I'm having difficulty with shifting on the front derailleur. If I try to downshift from the 50t ring to the 39t ring, it often skips all the way down to the 30t ring, and then shifting up usually requires two shifts, and to get it ideal it's usually two full shifts plus some trim adjustment.

Now I replaced the whole drive train (Ultegra 6600 shifters, Ultra 6703 FD, 6700 RD, 5703 Crankset) a few weeks, so I wonder if perhaps the issue is that the drive train wasn't completely properly installed. The front derailleur never shifted well (it would over downshifted maybe 10% of the time almost immediately, but I didn't down shift a lot so it wasn't super noticeable), but the rear shifting was pretty good.

It has occurred to me that this could be an issue of a bent derailleur hanger - I park my bike at work in a clearly inadequately bike parking situations, so I've wondered if someone has banged their bike into mine possibly bending the hanger. How hard would the bike need to be banged in order to cause that problem? Or is it possible that the upgraded drive train wasn't completely properly installed in the first place? I doubt it's a problem with the cables since they were also replaced with brand new cables, but I guess that's possible. Or could this be a compatibility problem between the 6600 brifters and the 6700 derailleurs?

I'm not going to do the work myself, I am going to go back to the shop that did the work, but I'm trying to inform myself about this as much as possible. They have said that they guarantee their work, but how can I determine if the problems I'm experiencing with the shifting are a function of a poor installation versus something that has happened to the bike in the interim (e.g. my theory that someone may have banged into it). How much should I be responsible for paying to getting the shifting to work properly?

Thanks,
Brad
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Old 05-22-16, 12:10 AM
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dksix
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My first guess would be cable drag, was it all new cables and housing when you replaced components? I think the 6600 shifters should pull the right ratio for the 6700 DR's. When I had shifting problems that seemed to be within a range if shifts like you are describing it was my cables/housing. and the rear hanger was bent just a bit but that wouldn't effect front shifting.
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Old 05-22-16, 12:34 AM
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bhdavis1978
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All new housings and cables, which is why I think it's probably not the cables. I was wondering if maybe the front der is slightly misaligned and that's complicating getting everything tuned in nicely.
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Old 05-22-16, 12:42 AM
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When I used to do full group installs, with new cables, we would always encorage the owner to bring it back in after a few hundred miles for a free adjustment to correct for cable issues. I can understand if they didn't/don't offer such a thing, but would hope that they would oblige, but I/we don't know your shop. If it does require a derailer hanger adjustment and they know they already did that in your build, you might be on the hook for some part of the labor cost. If They didn't check it or don't know if they checked it, it's time to find a new shop or start doing your own work.

You say you've already done some barrel adjustment and it's not helping. I wouldn't go fiddling with the limit screws if you intend to take the bike back to the shop and expect free service. But if the rear derailer is correctly set up, before you started messing with the barrel adjuster, it will be bent inward, and should have had a hard time falling into the highest gear, not the 23. Even if the cable housing compressed (cable stretch), the high limit screw would still be in effect. At any rate, at this point of frustration is where I detach the cable, detach the derailer, check my der hanger, reattach der, set high limit with no cable, attach cable, set tension.

As for the front derailer, it's hard to say without looking at it. But it doesn't look good to me that nothing shifted well from day one. Also, triples suck
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Old 05-22-16, 01:07 AM
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Just some ideas, what I'd check:

If brake housing (5 mm wide, instead of compressionless 4 mm wide) was used for shifter cables as well, that could be causing problems.

Poor cable and housing routing.

Bent RD hanger.
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