[Closed] Creaky XT cranks?

It does sound like the splines as you say. I've other thing to try : stood on the bike with the pedals level, try jumping and forcing weight down through the pedals. First left foot forward then repeat right foot forwards. You can even do this without a chain. Basically this will unmask a spline issue but eliminating the drivetrain. Your issue could plausibly still be chairing bolts etc.

I'm sure the XTs are pretty good but not immune to spline issues. I ran m770s for 5-6 years and took them on and off 30+ times. They're still going strong.

do they just wear out with extended use?

No. Only if they come loose and rotate round, which ruins the NDS arm splines every time.

Superficial, Could you prognosis also be caused by wear on the axle around LHS bearing? I suggest this as my crank has a small amount of play if I do as you say and rotate pedals from left to right foot forward. I have been trying to work out the cause and on inspection have noticed some wear marks around bearing/axle interface (m975).

Have you cleaned and greased the axle and splines?

@superficial thanks I'll try that.

They've not been run loose rotationally, they were slightly loose laterally when I first noticed the issue, but tightening didn't fix it.

@asdfhjkl yes but no harm to try again

Thx chaps.

Hm, I have a creaking NDS crank, and on removal, the spline looks less than perfect. Could have moved about and started wearing. It's only out of the saddle stuff, but it's now every time..

> It's only out of the saddle stuff, but it's now every time..

Yeah that's how it starts. I happen to have been doing a few road miles recently so pushing a big gear up smooth climbs and it was driving me crazy. It's actually much less noticeable on the trail.

But once it's in the head it has to be sorted. And a zero tolerance policy for creaks is no bad thing in case they're masking something else.

I'd recommend removing, cleaning and refitting the chainring bolts with shimano anti seize

Then doing the same with the crankset, remove the twin pinch bolts on the non-driveside arm, clean the threads in the arm, refit the bolts with Shimano anti-seize, good smear of anti seize on the axle splines and 13nm on both pinch bolts with a torque wrench

Had this last week with a Deore chainset...my moneys on it needing new bearings, as above, grease everything first in order to rule out bb shell, pedals, splined interface etc.

Thx, but nah the bearings are new, and switching the crankset for another fixed it. I do suspect it's the cranks.

Superficial, Could you prognosis also be caused by wear on the axle around LHS bearing? I suggest this as my crank has a small amount of play if I do as you say and rotate pedals from left to right foot forward. I have been trying to work out the cause and on inspection have noticed some wear marks around bearing/axle interface (m975).

Errr, potentially I suppose but more likely to be the splines IME. If there is significant movement in the splines then you can feel it through the pedals, and you may feel the pedals rotate a degree or so relative to each other. Stomp on the pedals a few times, if it's the splines it'll usually only creak on the first stomp (until you turn them 180 degrees and try the other way).

What are M975? Do you mean M970? They're a slightly different axle setup compared with XT (Although the same logic still applies).

I think they are m975? Maybe 970, they look the same. Yes splines are bigger/wider, but it could be them, although being bigger they would be a lot easier to see damage

Usually by the time you can see damage with your eyes it's waaay too late.