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Old 05-02-08, 06:06 PM   #1
rcaddy27
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loose left crank arm??

I have never had this happen before. Was riding last night and noticed a strange wobble in my pedal stroke. Took me a minute but when I looked down the left crank arm was rocking around in less than a perfect circle. It was loose from the axle.
I had no tools, so I hand tightened the crank arm bolt and soft pedaled home. Note to coaches-one legged pedal drills suck when you can't switch legs!
It is a steel Campy Centaur square taper and I have 2 questions,
1. If I don't have a torque wrench can I over tighten the bolt or can I just crank it tight and not worry?
2. How likely is it that I could have rounded out/striped/ fubar'd the crank arm from riding it loose for a few miles? I have been training and racing on this set up until the other night with no problems.

Thanks!
Roger
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Old 05-02-08, 06:08 PM   #2
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1. Highly unlikely assuming you're using the standard 8mm, you'd have to superman it
2. Very likely

There's nothing you can do except torque it up to spec real tight and hope it doesn't keep repeatedly coming loose. If it does, you're ****ed. Go look for a new crank. And next time use a torque wrench on the crank bolt if your hands are not familiar with the spec required.
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Old 05-02-08, 09:16 PM   #3
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I've saved damaged crankarms by beating the deformed aluminum around the square taper back into shape with a ball-peen hammer, but that's pretty sketchy. Doing that to a Campy crank might make me cry. Better than throwing it in the garbage though, I guess.

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Old 05-03-08, 02:34 AM   #4
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Originally Posted by rotarepo View Post
1. Highly unlikely assuming you're using the standard 8mm, you'd have to superman it
2. Very likely

There's nothing you can do except torque it up to spec real tight and hope it doesn't keep repeatedly coming loose. If it does, you're ****ed. Go look for a new crank. And next time use a torque wrench on the crank bolt if your hands are not familiar with the spec required.
+1

If your crank comes loose, you are best off not using it at all. There is no such thing as "soft pedaling". You probably did not damage the threads on the spindle or the bolt, but you almost surely compromised the aluminum crank. The crank has to fit onto the BB spindle (axle) EXACTLY. If there is any play due to you goring the crank hole, it will never fit right. If that is the case, you can get a new crank OR, you can be a tightwad and try to shim the crank hole with some aluminum foil. I've done it and it is tricky to get right. Eventually, you end up getting a new crank arm anyway.
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Old 05-03-08, 02:38 AM   #5
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I've saved damaged crankarms by beating the deformed aluminum around the square taper back into shape with a ball-peen hammer, but that's pretty sketchy. Doing that to a Campy crank might make me cry. Better than throwing it in the garbage though, I guess.
Don't throw that Campy aluminum crank away! Give the crank to the local aluminum can collector. There must be 100 soda cans in that crank.

Let's all take a sip from our beer cans and imagine that our beer is in cans made from a Campy crank!
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Old 05-03-08, 04:18 AM   #6
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If you got lucky you might be able to find a mismatched crank arm for sale used from a poor soul who did the same thing you did but on the other side...
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Old 05-03-08, 01:27 PM   #7
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is common for the left arm to come loose..not so common for the right.

my shop sells left arms seperately.
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