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Old 09-13-02, 02:07 PM   #1
ptmurphy
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Triple Shifting Problem

I have been searching the archives of this forum and the newsgroups for an answer to this with no luck. I actually bought a book on bicycle maintenance to try and fix it as well - no luck.

Anyway, I am having problems shifing from the small chain ring to the middle one. When I click the lever over the chain moves over but does not catch on the middle chain ring. It just hangs in limbo making a buch of racket.

Now, one of two things happens - 1) I hit the lever again and the chain immediately goes to the big chain ring, or 2) I keep pedaling, trying to get it to engage the middle chain ring and the chain falls off around the bottom bracket.

The bike is a new (400 miles) Cannondale R700. It has done this from the beginning. The bike shop says there is nothing wrong. The maintenance book only talk about outer adjustments (middle to big and middle to small limit adjustments) which are fine.

Any help would be GREATLY appreciated on this one.

Thanks,

PTM
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Old 09-13-02, 02:47 PM   #2
mechBgon
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For starters, with most Shimano STI shifters, if you punch in an upshift on the front derailleur, it's helpful to push the shift lever and hold it in, to help the chain engage the next ring, then release once the chain's got a grip on the ring. When you hold the lever, the derailleur cage is held a bit further out than its final resting position will be. When you release the lever, it settles back a touch. The LBS people may be so used to this aspect of shifting STI levers that it comes naturally, resulting in the "nothing's wrong" verdict.

There have been some Shimano STI levers where swinging the shifter did park the derailleur's cage precisely on its final position. No overshoot. If the final position wasn't enough to get engagement, there really was no option but to feint a shift from there to the big ring in order to get engagement, then cancel. I'm specifically thinking of old Shimano RSX 7sp here. I hope your levers aren't following in that tradition.

edit: I went to see what the R700 Triple comes with. Nice to see it has 105 levers, which have two trim positions for the middle chainring and aren't cursed with the no-play problem Try the force-feeding technique I mentioned, and punch in a trim on the downshift lever after shift completion... this is SOP for STI.

Last edited by mechBgon; 09-13-02 at 02:54 PM.
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Old 09-13-02, 03:37 PM   #3
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Besides what mech said, the LBS is blowin sheet in you.They likely have some moron wrench that does not know how to adjust it. Try www.parktool.com for help on derailer adjustment.Triples can be a bit tricky,but they can also be made to work well.Helps to know the drill yourself.
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Old 09-16-02, 09:54 PM   #4
ptmurphy
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Thanks guys. Holding the shifter over does seem to be resolving the problem for me.

Seems like the guy at the bike shop would have noticed what I was doing. I took him out in the parking lot and made it do it.

Thanks again.

Phillip
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