Cyclocross - chain sucks

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telos469

08-04-08, 11:49 AM

hey all,

I have an '07 Bianchi Volpe. Great bike, I like it lots but I have a problem: When cruising along at a fast cadence if I'm shifting up, occasionally my chain will stay hung up on the smaller ring, at the bottom, while at the top of the ring the derailluer is doing its job moving me up a gear. What happens is the chain wraps around the bottom of the smaller ring until I pedal to a point where there's no more slack and my chain jams, pedals stop, progress ceases. I've broken one chain from this already. I also have a Fisher mtn bike and it has what's called an "anti chain suck bracket" so obviously this isn't an uncommon problem, but I cant find anything that will fix MY problem on my Bianchi. Any Ideas?

timcook

08-04-08, 08:40 PM

Have you adjusted your derailers recently? There are a couple of good videos showing how here:
http://bicycletutor.com/adjust-rear-derailleur/
and
http://bicycletutor.com/adjust-front-derailer/

jonestr

08-05-08, 12:22 AM

From your description it sounds like you may have worn out your small chainring. To check this you should see if the teeth look sharpened. On a new chain ring the teeth are dull and have some radius of curvature between teeth. As the chainring wears then the valley will become larger. I am guessing that the valley now has a large enough radius of curvature that it is holding on to the chain too much. If this is the case then you need a new chainring. Although the rub is that chainrings, chains, and cogs all wear together so, unless you have been vigilant about changing your chain as the chain stretches (actually bushings being worn.), then you really need all new drivetrain stuff.

It may also be some kind of burr on the small chainring. If that is the case then you might just file it down.

Hope that helps

telos469

08-07-08, 09:41 PM

thanks for the input people!
that bicycletutor.com is awesome!
Il check out my chain and sprockets tomorrow however I doubt its worn very much as the bike only has about 1500 miles on it and a 2nd chain. Still I'm going to check it out in the morning.
HOWEVER I just found this:http://www.bikepro.com/products/chains/chainretainer.html