XTR Crankset fitment problem

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muddi camel
Posts: 60
Joined: Fri Mar 16, 2012 15:39 pm

XTR Crankset fitment problem

Postby muddi camel » Tue Aug 27, 2013 07:34 am

Got a weird (to me anway) problem.
Trying to fit a FC-M970 crankset to my mates MTB frame. It appears as though the crank axle is too long....
It's a 68mm shell, using a third party BB (that appears the same dimensions as most of this style).
I've had to fit in as many spacers as I can lay my hands on, & still can't get rid of the endfloat without the adjuster coming off the non-drive crank.
To keep the chainline right, I don't want any spacers on the drive side really, and any more than two spacers leaves insufficient thread in the BB to engage in the frame properly.
I'm not aware of an XTR specific BB having significantly different dimensions (2-3 spacers worth), so I'm scratching my head on this a bit. I feel I'm missing something obvious......
- Any thoughts?

thanks

Chunkers1980
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Joined: Tue Feb 10, 2009 14:12 pm

Re: XTR Crankset fitment problem

Postby Chunkers1980 » Tue Aug 27, 2013 07:39 am

So how many spacers have you used? Have you followed the instructions in the tech doc?

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njee20
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Joined: Mon Nov 26, 2007 20:06 pm

Re: XTR Crankset fitment problem

Postby njee20 » Tue Aug 27, 2013 07:49 am

You need 2 spacers on the drive side (unless he's using an e-type mech) and one on the NDS.

If you really want you could move them to the other side, but then the cranks won't sit centrally in the frame. If the chain line is that far off then something is wrong with the frame.

You say you've fitted as many spacers as you can "lay your hands on", but have none on the DS and only 2 on the NDS. Make sure you double check any safety critical stuff before you give it back to your mate!

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The Rookie
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Joined: Thu Apr 30, 2009 09:29 am

Re: XTR Crankset fitment problem

Postby The Rookie » Tue Aug 27, 2013 10:19 am

muddi camel wrote:Got a weird (to me anway) problem.
still can't get rid of the endfloat without the adjuster coming off the non-drive crank.

Eh, as you unscrew it to come off you loose preload, try screwing it in!

MichaelMLFC92
Posts: 350
Joined: Fri Jan 27, 2012 17:14 pm

Re: XTR Crankset fitment problem

Postby MichaelMLFC92 » Tue Aug 27, 2013 16:51 pm

Eh, as you unscrew it to come off you loose preload, try screwing it in!


M970 cranks are preloaded with a nut type thing on the inside of the non drive side arm, such that unscrewng it makes it closer to the BB. Unlike XT or SLX where unscrewing would move it outwards, away from the BB.

A 68mm BB shell needs two spacers on the right, and one on the left.

muddi camel
Posts: 60
Joined: Fri Mar 16, 2012 15:39 pm

Re: XTR Crankset fitment problem

Postby muddi camel » Tue Aug 27, 2013 22:39 pm

It's currently fitted with 4 and a very slim (almost a shim) spacers.
I can't see the frame being out of line - but I guess it doesn't take much....
I'll check alignment as best as I can in the morning.

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njee20
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Joined: Mon Nov 26, 2007 20:06 pm

Re: XTR Crankset fitment problem

Postby njee20 » Wed Aug 28, 2013 06:23 am

Are they the correct spacers, or some that were lying around? They should be 2.5mm.

Chunkers1980
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Joined: Tue Feb 10, 2009 14:12 pm

Re: XTR Crankset fitment problem

Postby Chunkers1980 » Wed Aug 28, 2013 19:42 pm

Shimano have started knocking out 2mm and 0.5mm as separate spacers recently.


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