Technical > Transmission

XT cranks working loose


I have noticed that the crankarms on my Nomad are working loose ... they are the ones with the splined BB, and the allen screw that is attached to the crank [self-extracing] ...

I did manage to really give them a good tighten yesterday once I got home with a real allen key, rather than the 8mmm one on an alien multitool ... I am thinking thta maybe I didn't tighten them fully on the initial build up ... but otherwise any thoughts???

timaru/oamaru, new zealand

Two things:
1. They need to be tightened correctly to start with.
2. They need to be checked after a few hundred miles after they have bedded in.
Don't worry too much.

Hi Hoogie.

I'm riding a 62" fixed with a Stronglight single-ring track chainset, together with self-extracting bolts. The bolts / cranks were always working loose. In the end I removed the self-extracting bolts and caps, put in "normal" bolts with a 8mm head and they have been rock solid for the past 6 weeks.
In your case I'd also check the splines for wear that may have already occured during the loosening. If this has already happened, no amount of extra tightening will stop the movement and the wear will get worse.
Hope that this helps you further.

Hoogie, I'm not sure of the exact torque setting to tighten cranks, but limit of strength with an 8 inch spanner is about right for conventional cranks. I use a thin smear of grease. Afterwards, I tighten after every ride, not to the original torque but about half the amount. I need to do this less and less.
 I'm not sure if it's the same for splined cranks. Hope this is of some help.


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