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Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

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Old 06-10-10, 02:56 PM   #1
notoriouslyKEN
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Pedal broke off in the middle of a ride

I was riding home from work today and my pedal was making weird noises (almost like a screech when I pedaled). I stopped to look at it but I couldn't discover anything weird or where the noise was coming from. Sure enough, about a mile later, my pedal snapped off. Luckily, I wasn't on a main road or anything and I was able to maintain my balance. This bike has about 75 miles on it and this was kind of unexpected. I think I can fix it if I take a rubber mallet and hammer it in. I took a few pictures though because it looks a little jammed up inside the pedal. It seems like an easy fix, but I don't want to risk it happening again. Does the pedal part look broken? Should I do it myself or call the shop I bought the bike from?

pedal2..jpgpedal1..jpg
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Old 06-10-10, 03:03 PM   #2
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The shop failed to tighten the crankarm prior to sale.
This is SOP in good bike shops.
Take it back and get a free replacement.

Enjoy

Last edited by powers2b; 06-10-10 at 03:03 PM. Reason: Because i am the GOD of my posts
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Old 06-10-10, 03:06 PM   #3
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Its a crank arm not a pedal. Powers2b is correct return it to the shop.
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Old 06-10-10, 06:01 PM   #4
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Thanks for the advice. I won't try and put it on myself. I knew it wasn't the pedal that broke off, but I didn't know the term for it. Hopefully the shop will fix it for free.
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Old 06-10-10, 07:24 PM   #5
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Thats fix is super easy if you have the tools and the bolt that goes in there. Good luck with the LBS
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Old 06-10-10, 09:31 PM   #6
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Thats fix is super easy if you have the tools and the bolt that goes in there. Good luck with the LBS
If you mean that it is simple to bolt the crank back on, yeah. But that crank is now toast, it is distorted and will not stay tight.
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Old 06-10-10, 09:47 PM   #7
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plus he probably lost the bolt or nut that hold it on because he did not notice it fall off. I've had this happen before. it sucks.
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Old 06-11-10, 08:53 AM   #8
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If you mean that it is simple to bolt the crank back on, yeah. But that crank is now toast, it is distorted and will not stay tight.
+1. OP should insist on a new crankarm. Aluminum crankarm vs. steel bottom bracket spindle = crankarm loses every time.
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Old 06-11-10, 09:10 AM   #9
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+1. OP should insist on a new crankarm. Aluminum crankarm vs. steel bottom bracket spindle = crankarm loses every time.
And it's no guarantee that the bottom bracket spindle isn't damaged.

If it is damaged, the bottom bracket is toast, too.
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Old 06-11-10, 09:34 AM   #10
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The spindle is probably not damaged. The crank is much softer than the spindle so it can't exert much damage on the spindle, if any. True, there's no guarantee, but damage isn't all that probable.
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Old 06-11-10, 09:45 AM   #11
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A crank falling off on a new bike should definitely be covered under warranty. If the LBS won't replace the arm for free call the manufacturer.

If the bike were older I'd be telling you to be more attentive since this was pretty noisy for a while before it got to the point of falling off. Either way the spindle will be fine, but even without seeing the photos I could tell you that in all likelihood the crank arm is toast, because riding it a while loose would have distorted the square hole irreparably.

BTW- watch the mechanic do the repair, if he doesn't take 10 seconds to also check whether the right bolt is tight, he obviously doesn't care about the quality of his work and you should find a new LBS.
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Old 06-11-10, 11:10 AM   #12
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I do have the bolt, but it sounds like this crank arm is no good now. Hopefully the shop will take care of it. I am going to contact them after I get off work today. It was noisy when I was riding and I stopped to try and figure out what was going on, but I couldn't see anything wrong. I assumed the bike needed some lube on the pedal somewhere and was going to further investigate when I got home. Unfortunately, the bike didn't last that long.
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Old 06-11-10, 12:18 PM   #13
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And it's no guarantee that the bottom bracket spindle isn't damaged.
I'd say it's a guarantee.
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Old 06-11-10, 01:48 PM   #14
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I'd say it's a guarantee.
Damage to the spindle does happen... i have seen a spindle polished by a loose crankarm that is repeatedly retightened and repeatedly fell off, then subsequent crankarms fall off after being properly tightened.
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Old 06-11-10, 02:18 PM   #15
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This is my version of crank-arm fail. Russian crank XB3 from 1973 from a fixed gear, failed when I was gently descending from a small kerb. (It was old and an unsuspected crack into the metal was slowly and sure propagated until it was too weak) Fatigue fail from hard riding from 1973 to 2009.


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Old 06-11-10, 02:37 PM   #16
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Damage to the spindle does happen... i have seen a spindle polished by a loose crankarm that is repeatedly retightened and repeatedly fell off, then subsequent crankarms fall off after being properly tightened.
Some people just like to argue. Read the OP. The crank arm fell off, for the first time, on a practically new bike. The spindle is fine, he needs a new crank arm.
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Old 06-11-10, 02:38 PM   #17
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BTW- watch the mechanic do the repair, if he doesn't take 10 seconds to also check whether the right bolt is tight, he obviously doesn't care about the quality of his work and you should find a new LBS.
He should pull the crank. One of the defects of tapered spindles (one of the few, other than they're a bit heavy, and last forever, if they don't have stupid bearings) is that the crank arm will wiggle up the taper. That removes some of the preload on the fastener. So the bolts will seem loose, even if the crank is on the taper properly. Checking the tightness of the fasterns results in them being tightened, which will distort the taper, or cause the crank to split (like this one: http://pardo.net/bike/pic/fail-001/FAIL-005.html )
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Old 06-11-10, 03:02 PM   #18
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Some people just like to argue. Read the OP. The crank arm fell off, for the first time, on a practically new bike. The spindle is fine, he needs a new crank arm.
Some people do like to argue. Some other people like to pretend they know more than they really do. I am not saying the crank is damaged, just that damage is possible and the OP's bike is not guaranteed to be free of damage.
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