Singlespeed & Fixed Gear - Crank/Chainring/Chain/Cog/??? Problem!??

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kahoon
08-21-09, 12:15 PM
Thanks in advance for your help!

For the life of me I can't seem to figure this one out! I have a stock Felt TK3 with a driveline thats completely out of whack. My chain seems to be very loose in one position of the cranks, and very tight 180 degrees from that position http://www.advrider.com/forums/images/smilies/headscratch.gif http://www.advrider.com/forums/images/smilies/puzzled.gif Initially, I was pretty sure that my chainring was not perfectly round (albeit very not perfectly round), so I rotated it a notch on the crank to see if the situation changes, and it didn't! I tried rotating the chain to a new postion, still nothing. ratation the cog, also nothing. Now I'm suspecting that my Crank spider is the culprit! Maybe one of its legs is out of whack!

What do you guys think?

Thanks again :thumb:

jpdesjar
08-21-09, 12:24 PM
It sounds like it's your chainring needs to be centered.
What type of crank/chainring do you have?
Loosen the chainring bolts and make sure the ring is centered, then tighten them down skipping every other one.

Also, I think most chainrings are not perfeclty round. Higher quality rings are more round than cheaper ones.
ianjk
08-21-09, 12:31 PM
http://sheldonbrown.com/fixed.html#tension

kahoon
08-21-09, 12:40 PM
It sounds like it's your chainring needs to be centered.
What type of crank/chainring do you have?
Loosen the chainring bolts and make sure the ring is centered, then tighten them down skipping every other one.


I've already tried that according to Sheldon's article, but there doesn't seem to be much movement in the chainring. Besides, the difference in tightness in the chain is far more than a re-centering could fix.

I have the stock Felt Crank/Chainring, 144BCD, 48tooth and 3/32 chainring.

Any other idea's?
jpdesjar
08-21-09, 12:44 PM
I've already tried that according to Sheldon's article, but there doesn't seem to be much movement in the chainring. Besides, the difference in tightness in the chain is far more than a re-centering could fix.

I have the stock Felt Crank/Chainring, 144BCD, 48tooth and 3/32 chainring.

Any other idea's?

I can't really think of what else could be the cause of this tension problem.
I just thought it was normal for a chain to be taught in one position and loose in another due to the chainring. How does it feel when you ride?
Perhaps your chain is too tight?
kahoon
08-21-09, 12:54 PM
I can't really think of what else could be the cause of this tension problem.
I just thought it was normal for a chain to be taught in one position and loose in another due to the chainring. How does it feel when you ride?
Perhaps your chain is too tight?

actually its the opposite. i'm worried that the chain is too loose. i cant tighten it any more because that causes the tight spot in the chain to be WAY too tight.

the bike rides fine with no issue.