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Old 07-21-08, 05:50 PM   #1
Maestro
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Upshifting issues (in the front)

I've put together a bike on Nashbar Touring frame and I have an issue with from derailleur.

The derailleur is Tiagra, and the crank is Nashbar Trekking crank (48/38/28)
Everything works ok, except:

When upshifting from middle to large, chain "binds" between derailleur inner plate and large chainring - so there is high resistance for rotation of cranks - and when I "force" it through, chain is picked up by large ring and everything is normal from that point on.
The derailleur is adjusted by Shimano instructions... I can't figure out what's wrong. The only thing that I suspect is that it's too low on a chainring.. but it doesn't appear so. Could that cause this kind of behavior ?

I'd really appreciate some advice on this

Thanks
-MB
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Old 07-21-08, 07:46 PM   #2
joejack951
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Are you finding this binding while working on the bike on a repair stand? The first time this happened to me I thought something must be wrong and fiddled and fiddled and got nowhere. Finally, I tried shifting out on the road and it was fine. I've since learned not to care too much about how a bike shifts on a repair stand and always make my final adjustments out on the road.
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Old 07-21-08, 10:38 PM   #3
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Too little clearance could cause this problem, as you rightly suspect. See if moving things up a couple of mm fixes things...
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Old 07-22-08, 11:15 AM   #4
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Is the big chainring facing the right way, with the chain-peg facing out?

This can also happen when u shift while pedaling too slowly as mentioned.
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Old 07-22-08, 11:59 AM   #5
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Make sure your FD is aligned correctly. That is, the outer-cage is just 2-3mm above the large chainring (I prefer 1-2mm). If your outer-cage is rotated correctly to be parallel to the chain in the highest gear (big-chainring/smallest-cog), it helps shifting up to bend the tip of the inner-cage outwards slightly. This helps shove the chain upwards and outwards.

Also use lower gears and spin faster. The higher speed and lower chain-tension will help it shift much better. Experienced riders learn to lighten up on the pedals slightly when shifting the front.
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