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Old 03-20-09, 06:57 PM   #1
nesdog
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FD not always holding chain in big ring

I've got a 5-1/2 year old OCR2 with Tiagra FD, triple gear set.

When I shift from the middle ring to the big ring, the chain doesn't always stay there; it will simply drop back down. Doesn't matter whether I hold the shifter for long or short. Happpens about 40% of the time.

The shifters are pretty new Ultegras. I've had the bike to the LBS a few times for adjustments yet the problem persists.

So I'm wondering if the problem could be with the FD rather than the cabling? Is there any shelf life to a FD?

Any other suggestions welcomed!
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Old 03-20-09, 07:18 PM   #2
joejack951
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The problem is likely that you have too little cable tension. You can easily verify this. Attempt to shift into the big ring extending the front derailler as far as the shifter will move it. Place the chain on the big ring by hand. Now, see if you can move the derailler further away from the bike by pushing/pulling on it by hand. If it moves considerably, you do not have enough cable tension as the derailler has not reached it's outward stop. Turn the barrel adjuster for the front derailler a half turn and try shifting again. Keeping adding turns at about 1/4-1/2 at a time until the shift completes without hesistation. If after adding tension your chain starts to fall off the outside of the big chainring, you'll need to reset your high stop. We'll address that when the time comes though.

You'll know you've added too much cable tension if you can no longer downshift to the middle or small rings. Try not to do that

BTW, if your LBS could not fix this apparently simple problem, I'd suggest finding a new one.
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