I want to swap my m770 3x10 XT cranks for 2x10. I want lighter and a narrower q-factor. I would like to keep my current XT shifters and FD if possible but i still want good performance. I am looking at XX or XO in 26/39 and m980 XTR in 26/38. The SRAM q-factor is listed at 166 i cannot find info on the XTR. My current XT is 175 q-factor The prices are similar between them except the XTR comes with a BB. What do you think my best option would be?
Be aware there are two XTR crank versions:
FC-M985 'Race' 2x10 only
FC-M980 'Trail' 3x10 and 2x10
The M985 has a narrower q-factor than the M980. Do a search the and figures are on here somewhere.
One important consideration with the M985 is that because of the low q-factor, the crank can clash with the chainstays of many frames. Do your research before buying. For instance my Cannondale Flash driveside chainstay has about a 2mm clearance with the M985 crank.