XTR M970 BB Bearing adjustment

[Weight Weenie]

Hey guys

 

I recently upgraded from xt to xtr and had the lbs install the crankset.

 

I've gone for a ride or two but the when turning the cranks they sound very rough, it's not a grinding/clicking sound. It's difficlut to describe. 

 

I'm guessing  that either the frame was not raced/faced (?) properly and the bb might have gone in skew or the preload is wrong, and that is whats causing the noise.

 

Please advise tech-heads

 

Thanks,

WW.

[Little-Ben]

check your chain is not rubbing on the front derailer,

 

is it a new BB and crank set

 

 

[Weight Weenie]

Yep its brand new crankset incl bb

Have checked, chain isn't rubbing.

 

Any other ideas?

[Johan Bornman]

The new XTR cranks have a thurst adjuster system. It is a fancy word for adjustable spacer. I could envisage that if this spacer is adjusted too tight against the BB itself, it would create a grating noise. I haven't seen this happen yet, but it could be.

 

Look at the left crank. You'll see a ring that locks with a small allen key. Loosen this allen screw a bit and turn the ring anti-clockwise so that it does not make contact with the BB at all. Now spin the crank and see if the noise is gone. If it is gone, you know the source of the noise and you can take steps.

 

I suggest you remove the chain during these tests just to eliminate anything else.

 

 

[Weight Weenie]

Dankie Johan sal gan vroetel