I have a dub crankset with arm length 175 (https://www.sram.com/en/truvativ/models/fc-styl-7k-b1)

I want to change the crank arm length to 167.5

There's no 167.5 crank arm for SRAM MTB line (I think SX/NX/GX/XX1/X01 are MTBs?)

I found Red and Force 167.5 arms which are also DUB (I think these Red and Force are for road?)

So can I mix the Red or Force crank arm (https://www.amazon.com/SRAM-Force-AXS-Crank-Assembly/dp/B07WCRY3BY) with my existing MTB crankset ?

  • Is there a reason you are set on 167.5mm instead of 165mm or 170mm? A 2.5mm difference is likely smaller than most people can notice. It seems likely that either of these common crank lengths would be OK for you.
    – Weiwen Ng
    Dec 22, 2020 at 18:08

1 Answer 1


Road cranks are not going to work on your MTB.

The crank arms include the crank axle - one of the arms is permanently attached to the axle. The axle length is important. Road bikes use narrower bottom bracket shells than MTBs and hence have shorter axles.

  • Thank you...! might require a new question but.. would lightningbikes.com/store/index.html#!/Lightning-MTB-cranks/p/… this work for me? they have osbb (specialized) listed.. but don't say dub.. does that mean, I'll have to buy osbb bottom bracket as well to use the crankset?
    – eugene
    Dec 22, 2020 at 15:12
  • Personally I would not touch a carbon crank from a manufacturer I have never heard of. What you should do at this point is learn a bit more about bottom bracket standards so you wont have to keep asking if certain cranks fit your bike. Start here and here. Dec 22, 2020 at 15:50
  • Also make sure you understand chain-line. That's the distance from the center line of the chainrings to the center line of the frame. Different drivetrain setups require different crank chain-lines. This is related to the width of the rear hub and how far outboard the cassette is positioned. Dec 22, 2020 at 16:04
  • I tried reading that article about bottom bracket. just so overwhealming.. I guess i'll give it another try.. Thank you.
    – eugene
    Dec 22, 2020 at 16:07
  • @eugene Reading the crank specifications, they don't say what axle diameter they use. DUB refers to the crank axle diameter (28.99mm). Now, I have heard of Lightning during my weight weenie days, and I know these cranks predate the introduction of DUB. So, if you decide to get them, assume you will need to change your BB.
    – Weiwen Ng
    Dec 22, 2020 at 18:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.