Tech question: Deore 6120 and XT 8120 crank cross compatibility

I purchased the right sided XT 8120 stages power meter crank. Does anyone know if I can combine this right side crank with the Deore 6120 left side crank arm already on my bike? They appear to have the same design, but can’t be sure. TIA

It will work fine. Only m9100(?) isn’t compatible due to single bolt design.

You might want to check the q-factor after install by measuring the pedal mounting surface to downtube (pedals removed) - correct with pedal washers or crank spacers

Make sure you torque the pinch bolts to spec as it’ll impact PM results.


Thanks a ton for the help!

I did this with a MT510 (OEM Deore, designed to fit any bike) and M7100 SLX crank, it’s fine. Stages notes that some arms are thicker than others, but the difference is small and spacers exist. They just don’t want to answer a million spacer questions for individual combos.
Have you bought yet?

  1. If not, note the xx00, xx20, and xx30 arms are the same. I think Shimano just labeled them to be consistent with the drive side, which has the longer spindle.
  2. Note this low low price- 4iiii PRECISION Power Meter Shimano XTR FC-M9000 | The Pro's Closet (the SLX, XT, XTR arms are all about the same weight)
  3. I’m pretty sure the road cranks, GRX, and the xc/trail MTB hollowtech arms are more or less the same except for a 2.5mm spacer on GRX/ MTB arms at the spindle. If you don’t mind running a washer on your DS side / dealing with 2.5mm of offset q-factor, you can run the MTB arm on a road bike - you only need one PM.
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As noted, they’ll mount together just fine. Shimano has used the same crank axle/crank arm interface for a while now.

Looking at Shimano’s website, both have a q-factor of 178mm, so no need to play with extra spacers.

It’s usually the XTR (narrower) and sometimes DH/enduro (maybe wider) that differ. That, and you have to watch boost vs non-boost vs super-boost. And number of gears (or maybe better stated as component generation).

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