I've got some XT cranks, not the latest model, the one before. Anyway I set them up as per instructions no torque wrench but I was careful not to overtighten them. They've worked for ages no problems, a couple of weeks ago they worked loose, I retensioned them and tightened the pinch bolts. I replaced the bearings thinking them being worn may have caused it, I also cleaned the splines and cranks and fit them (without grease). On the nesxt ride they worked loose again, I tightened them up pretty tight but on sunday they worked loose again.
Any Ideas?
Fresh bearings, preloaded with the plastic wheel tool finger tight, properly tightened up (both bolts screwed in at the same time)
I dont want to pile on the torque any more as I'm afraid of stripping the threads, would greasing the splined or threadlock help?
tighten the bolts without a torque wrench (just use your judgement) - and use loctite.
Is the hex on the crank arm bolts become rounded? happened to me a while ago, i changed the bolts and everything has been fine since, i couldn't get the others tight enough as they were worn.
Nah Wors the bolts are fine, the bolts aren't coming loose the non-drive side arm just seems to be working loose.
Mr Crush rider, do you mean try loctite on the splined crank axle? As mentioned the 2 pinch bolts aren't coming loose.
Surely if you're saying the pinch bolts aren't coming loose, but the cranks are, there is a problem with the pinch bolts? The preload cap is just that, pre-load. Once you have tightened this to take up any play, then done up the pinchbolts, you can remove the preload cap. If you strongly believe you are doing them up tight enough, then it can only mean the interference fit between the spindle and crank arm is knacked. Suggest losing the torque wrench and just doing them up harder. Or its new cranks.
I can't understand either how the cranks are coming loose if, as you say, the oposing pinch bolts aren't themselves coming loose.
I had this crank loosening thing happen in the early days of running the XT Hollowtech 2 chainset where the whole assembly started creaking after a while on each ride. My solution was to replace the two rather short Shimano bolts with slightly longer ones. No Loctie, just longer bolts and the problem has never resurfaced.
Donk if you want to try some fresh bolts we have some at work. let me know.
The bolts definitley aren't coming loose. I'm thinking the interference fit maybe knacked as swift says. Hope not. When the crank works loose the bolts are still really tight, I have to undo them, retension the bearings then tighten up the pinch bolts. Thanks for the offer wors but I'm pretty sure the bolts are fine.
The wierd thing is how the problem developed, they had been running fine with no problems for ages then suddenly one day they were loose. Think I've got a visit from the bike faff pixies, replaceable dropout bolts and rear brake calliper bolts came loose on sunday too. Grrr
