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'bent bottom bracket / crank wobble

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'bent bottom bracket / crank wobble

Old 03-19-08, 01:06 PM
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'bent bottom bracket / crank wobble

does any other 'bent rider get this problem and is particular to 'bents, where you're pushing horizontally rather than putting your weight on it vertically?
the problem is the cranks make a clunk when you pedal, unless you really tighten the allen-key 'holding-in' bolts. it seems to wobble free quickly and further tightening (I think) has stripped the threads inside the end of the BB
Are the cranks incompatible with the BB? It's all original (as sold) equipment
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Old 03-19-08, 04:21 PM
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What you're describing is caused by riding with the cranks loose at the bottom bracket. Once you round out the inside of the bb/crank interface (the inside of the square taper,) then the cranks are toast because you'll never be able to keep them on after that. Bents use all standard parts. The condition is not peculiar to 'bents.

On second thought, there's an outside chance it could be a part compatibility problem. Square taper Shimano stuff does not work with square taper Campagnolo stuff - different taper rates - so you can't mix and match there. Once done, though, the solution is the same: replace the now-damaged stuff. I'm picking on square taper because that's usually the style that has the problem; but it could happen with Isis or Octalink, too.
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Old 03-25-08, 01:36 PM
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the BB is FIRST 68mm 1.37x24T F-2001SW approx 119mm, It has a separate bearing BRG 6002RS D16
I am trying a Shimano bracket from another bike UN53 68 BC1.37x24 approx 110mm
seems to fit OK - proof of the pudding will be seen tomorrow

by the way, I'm toying with the idea of getting a 58 chain ring (current one is 52) as I calculate that'll give me the top gear I miss sometimes and will lose the bottom one I cant be sure I need anymore. Current cranks are Airnimal - no other info
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