Chain Rub impossible to fix
12-16-06, 11:54 PM
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Chain Rub impossible to fix
No matter what i do i cant adjust the front derailler so that it doesnt rub, well anyway my question is i know 10 speed chains are thinner than the average 7/8 speed chains but can it still function on my 7 speed? and can it fix my problem?
12-17-06, 01:35 AM
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You probably have a chainline problem. This can often be fixed with a slightly different length bottom bracket. Your cranks are probably specced for a particular length BB - you should make sure that matches the actual length of your BB. Otherwise, you could just go up or down 1 size, depending on which side it rubs.
12-17-06, 07:03 AM
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You weren't very descriptive about which situations cause you to get chain rub.
On a lot of bikes with short chainstays, for example, it's normal for the chain to rub the inside of the big chainring when you're in the last couple little/little gear combinations. If that's the case, no amount of derailleur adjustment will fix it because the chain rub doesn't involve the derailleur.
On a lot of bikes with short chainstays, for example, it's normal for the chain to rub the inside of the big chainring when you're in the last couple little/little gear combinations. If that's the case, no amount of derailleur adjustment will fix it because the chain rub doesn't involve the derailleur.
12-17-06, 07:09 AM
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Originally Posted by Phoible
You probably have a chainline problem. This can often be fixed with a slightly different length bottom bracket. Your cranks are probably specced for a particular length BB - you should make sure that matches the actual length of your BB. Otherwise, you could just go up or down 1 size, depending on which side it rubs.
12-17-06, 10:11 AM
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12-17-06, 11:24 AM
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thanks for all your help guys but im going to bring it to my LBS and see what i can do about it thanks though
12-20-06, 09:48 AM
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I had the same problem and it turned out that my front derailleur was slightly off-line from the chain. Loosened the clamp, lined it up, and bingo - only the expected chain rub when cross-chained.
