Crank bolts and threadlock.

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Paulus

Started young, and still going.
Location
Barnet,
The crank bolt on the non driveside of my Campag Veloce chainset keeps coming loose after 50 or so miles, and the crank then starts to come off. It tightens up ok, but then the same happens agin after some milage. Would it be ok to use threadlock to hold it in place? I have stripped the chainset down and cleaned and inspected it, it seems ok. your thoughts please.
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
Yes if this keeps hapening.

Is this on the Power torque chainsets ?
 

Amanda P

Legendary Member
I've had this sort of problem. I'd suggest you take the crank off and have a really good look at it with a strong light and a magnifying glass. I'll bet there's a crack in it at one of the corners of the axle hole. It doesn't have to be big for the crank to be constantly loosening itself, and of course, when you're not heaving on it, the crack closes up and can be almost invisible.

If you've ridden with the crank loose for any length of time, the square hole gets rounded too - the alloy crank is much softer than the steel axle. Once this happens, you may never get the crank to stay on tight, crack or no crack.
 

02GF74

Über Member
if the crank is ridden when it has loosened off, the square hole gets rounded off which helps to get the crank loose again. the rounding off can be too small to notice but once it starts, there may not be much you can do to stop it.

I've had this poblem once and soloved it by using 2-part epoxy to "glue" the crank on to tapred axle, tightening it abit more than useal and possibly - can't remember now - using threadlock.

note here are different grades of lotcite - some are much stronger - get hold of some loctite studlock.
 

Globalti

Legendary Member
The only time I've broken a square taper crank it was the left hand one because there's less metal there....
 
OP
OP
Paulus

Paulus

Started young, and still going.
Location
Barnet,
Thanks for the replies. I will examine the crank in detail. Sounds like it may mean a new crank, if I can source one, or a new crankset.
 
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