Wobbly chain rings
05-06-11, 10:37 AM
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Wobbly chain rings
I'm noticing a wobble in the front chainrings. They all seem to be wobbling together. Did I bend my spindle? or something else?
05-06-11, 10:58 AM
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If you bent the spindle, the whole ring would be off camber, but you might have bent one of the spider arms. I'm not sure what you can do short of buying a new crank, but if it's not bad enough to cause shifting problems, just keep riding it.
05-06-11, 12:34 PM
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I don't think any of the arms are bent. The rings all seem nice and flat thought I haven't looked at them that closely. Just when I look down as I pedal the rings wobble in and out together. I do think the wobble is why I can't get my FD adjusted right. It seems like if I get it so the chain won't slip off the outside, then it is very finicky in shifting to the large chainring. If I get it so it shifts easily, then it seems like the chain falls off the ring half the time.
05-06-11, 01:37 PM
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If you are unsure what the issue is, take it you your LBS, they should be able to identify the issue quickly, and advise a resolution.
05-06-11, 02:24 PM
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For example, FSA ISIS cranks have a torque specification of 28 - 43 foot pounds. Mine weren't square when first installed at 30 something foot pounds and I had problems adjusting the derailleur so I could get reliable shifting without dropping the chain.
A little over 40 foot-pounds got them to seat right and allowed proper front derailleur setup.
05-16-11, 10:17 AM
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I picked up a bike to use for parts for a few bucks last week. Since then I noticed the wobble getting worse. I Didn't get the rear whell on tight and yanked it off when starting up from a stop like on Thursday. The spindle seems fine, no detectable wobble in it. So I swapped the crank arms and the new one is fine. I'm guessin I damaged the crank. On close inspection the square hole shows a very slight deformity (metal bulging on one side of the hole.
