Upshifting issues (in the front)
07-21-08, 05:50 PM
#1
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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
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
07-21-08, 07:46 PM
#2
Senior Member
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.
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...
07-22-08, 11:15 AM
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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.
This can also happen when u shift while pedaling too slowly as mentioned.
07-22-08, 11:59 AM
#5
Senior Member
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.
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.
