Bicycle Mechanics - Crank bent; Chain skips... Help?!?

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bobsaget
04-11-05, 07:02 PM
I recently bought a Specialized Hardrock Comp Disc. I have two problems with the bike that I would like to fix and just need a little help on identifying my problems. ;)


Problem #1

I think my crank arm is bent. It connected on the BB a little crooked.

Here is quick pic I drew up to help explain...

http://1stclasspcs.com/uploaded/cran.JPG


Where can I just buy a crank arm... I looked around and only saw cranksets.

Any help?


Problem #2


When I am in gears ~8-24 and I am trying to accellerate, it feels like the chain has skipped a link or two. The crank slips a little and then catches again. What is the problem here?




I would really appreciate some great advice... :) Thank you.

twahl
04-11-05, 07:12 PM
If the crank arm is bent, you will feel a definate wobble in the pedal. There won't be any mistaking it. The pedal shaft doesn't rotate in relation to the crank arm, so you would feel the wobble.

Chain skipping...is this a new bike? I'm not sure what you mean by 8-24, but if the bike is new you should have the shop check it out. If you're on your own, and the bike has some miles on it, could be that the chain is stretched/worn and/or the cassette is worn.
ivan_yulaev
04-11-05, 07:54 PM
1. Check cable tension...when the tension is off, you will miss shifts and the shifts you get will not be as crisp. The chain may rattle as the deralleur rubs it against the neighbor sprocket.

2. Some crank arms are like that. If it is bent OUT (very rare, a crash will usually bend it in) you will definitely feel something very strange, as the pedal axis will be out of the crank axis.