torque crank bolts to... ?
#1
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i ride a bicycle
Joined: Nov 2006
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torque crank bolts to... ?
Hey guys sorry I didn't search, but I need a quick answer and sifting through search results usually takes me longer than just asking a simple question.
I have a cup and cone, loose ball, BB with a square taper campy spindle on my peugeot fixie conversion. Bulletproof bmx cranks (budget reasons).
What is the proper tightening torque for the crank bolts? The cranks just started to get a tiny bit loose, hopefully I caught it before the cranks have been irreperably damaged. I originally tightened the bolts as tight as I could get them with a 3/8" drive wratchet wrench, but I'm guessing that's not tight enough. I have a 1/2" drive torque wrench. What's the proper torque to use this time?
Mac
I have a cup and cone, loose ball, BB with a square taper campy spindle on my peugeot fixie conversion. Bulletproof bmx cranks (budget reasons).
What is the proper tightening torque for the crank bolts? The cranks just started to get a tiny bit loose, hopefully I caught it before the cranks have been irreperably damaged. I originally tightened the bolts as tight as I could get them with a 3/8" drive wratchet wrench, but I'm guessing that's not tight enough. I have a 1/2" drive torque wrench. What's the proper torque to use this time?
Mac
#2
Sometimes the cranks loosen on the spindle after you initially tighten them and ride for a bit. I've heard that this is normal and also that it isn't... If I were you I would just tighten the hell out of them again and watch for loosening.
#5
live free or die trying
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From: where i lay my head is home.
Bikes: bianchi pista workhorse, cannondale r1000, mountain bike fixed conversion
Originally Posted by hockeyteeth
Sometimes the cranks loosen on the spindle after you initially tighten them and ride for a bit. I've heard that this is normal and also that it isn't... If I were you I would just tighten the hell out of them again and watch for loosening.
#6
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i ride a bicycle
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Originally Posted by Baube
if the hockeyteeth's solution didn't solve your problem, I wonder if the taper of the spindle is the same as the crank's one.
Mac
#7
Bulletproof and Campy don't mix. The damage won't be obvious until after a few hundred miles.
Originally Posted by sac02
I am a little worried about this; I read a little about it and it was always in the back of my mind when I put the bike together. I could never get a definative answer whether or not the bulletproof cranks and campy spindle had the same taper. They seemed to fit together ok, but I don't know how "poor" the fit should be if they are incompatible. Would it have been grossly obvious if they were?
Mac
Mac
#9
Originally Posted by Baube
is both of your crank loose?
How about a spindle beer can shim? that's one of those things that I've always thought to try, but never actually done, because I can't imagine it working. But I'd like to know.
#10
asleep at the wheel
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From: Chicago
Bikes: Custom Richie Ditta Track Bike, Eddie Merckx Corsa, Marioni Custom Pista, Dolan Cyclocross
Torque values for crank bolts are manufacturer specific. Pretty much need at least 300 inch/pounds and most are spec'd higher than that.
Theres some basic values here:
https://www.parktool.com/repair/readhowto.asp?id=88
Theres some basic values here:
https://www.parktool.com/repair/readhowto.asp?id=88
#11
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i ride a bicycle
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Originally Posted by AfterThisNap
Bulletproof and Campy don't mix. The damage won't be obvious until after a few hundred miles.
The problem is fixed for the moment. I torqued both crank bolts to 32.5 ft-lbs.
Also: when I got down there to really inspect things as I did the crank bolts, I noticed the adjustable side of the BB cup had come loose, about an eighth of a turn. The cranks were a little loose, but it turns out I was also feeling a little play in the BB itself. So that is now also fixed, we'll see how long it all lasts.
Mac






