SRAM X9 fat bike crankset with 100mm spindle

While Shimano may have unofficially created a one-off XT fat bike crankset, SRAM’s gone all in with two o-fficial cranks with the 100mm wide spindle.

Debuting in X9 and X5 trim, they’ll be available in 170 and 175 crank arm lengths with GXP spindles. Both use their 2×10 chainrings, and retail will be $314 (€280) and $169 (€151) respectively. Chainring combo is a smaller 36/22, and, from what we can tell, they’ve been optimized to improve chain/tire clearance versus their standard chainrings. BCD is a smaller 104 compared to the 120BCD on standard X9 cranksets.

UPDATE: Weights are 871g (X9) and 955g (X5) with chainrings and GXP bottom bracket. They’re designed with a 66.5mm chainline. The X9 uses hollow forged aluminum crankarms. The X5 gets forged, asymmetric arms.

More pics below…

SRAM X9 fat bike crankset with 100mm spindle

X9 frontal profile (above) and the X5 version (below).

SRAM X5 fat bike crankset with 100mm spindle


  1. “…from what we can tell, they’ve been optimized to improve chain/tire clearance ”

    any word on the chainline offset?

    “optimised” could mean anything.

    Some fatbike cranks are 66mm chainline. Some are 67.5, others are 73, some are even 82mm.

  2. All – SRAM just replied to our inquiry about that “optimized” bit, and they said there’s no specific offset to the rings, so it’s mainly the wider axle and specific spider that we’re thinking makes them “optimized” for fat bikes. That, and the lower gearing.

  3. Tyler. So basically that means they’ve stuffed up.

    For example, I know that a Race Face cranks will have tyre/chain rub problems with a 4.7″/4.8″ tyre in the 22/36 combo. And RF is using 67.5. Traditional chainline on an mtb crank is around 50mm.

    the E Thirteen XCX crank is 66mm and has the same problem with using the really fat tyres now in demand. and the TRS cranks that E Thirteen made for Salsa are around 73mm chainline.

    The Surly MWOD coming in at a massive 82mm.

    and SRAM can’t tell you what their offset is?

    +1 for effort
    -5 for detail.

  4. And Shimano claimed they do not want to make any.

    They should do SLX. It will sell. Quarter of the world is frozen half the time.

  5. @ bin judgin: I agree. In fact, there’s no reason for mountain bikes at all. I used to ride my 10 speed road bike on the trails when I was a kid back in the late 70’s early 80’s. Seriously though, I’ve ridden my mtb for years in the snow and there’s just no comparison to a fat bike, not to mention the other possibilities it opens up. Just did a 10 mile beach ride last night. Try that on a mtb.

  6. bin judgin-
    A lot of people might make the same “a fool and his money” comment about your choice of bikes. Why can’t people just respect everybody’s choice of bikes? Different strokes for different folks. After all, they are all bikes. Why the negative vibes?

  7. Can anyone confirm that the X9 spider is removable? One commenter above thinks it is. This would be great because I want to add an XX1 spider/chainring to the 100mm X9 and convert a Hope Pro2 Evo Fatsno 170mm rear hub with the freehub body they make for the XX1 cassette, so I can run a full XX1 drivetrain on a Beargrease.

  8. Forget it – I just got confirmation of my question above from Sram themselves. The 100mm X9 spider is indeed removable BUT it uses a different spline than XX1 so you can’t put the XX1 spider on the 100mm X9 crank in order to help create a XX1 FatBike drivetrain. Too bad.

  9. @Scott – you could run a NSB or an MRP single ring. You won’t get the magic teeth of the XX! (which really work) but you will get the clearance and clean look.

  10. You can typically fit the spiders on physically. The difference in chainline is somewhat in the SPIDER offset though, so it won’t line up PERFECT but you can do it. This is how MRP’s bling ring fits all the AKA/X9/X0 cranks the same way.

  11. The XX1 spider has a radical asymmetrical spider. Only the XX1 rings fit the spider. I lengthened the shaft to fit the 100mm shell no problem. If there’s interest, I’ll offer it as a modified crank to the public. (no SRAM Waranty)

  12. So could you not just add a homebrewed components single ring to the X9 crankset in say a 29t alu version and achieve the 1×10 that way without the all the fuss that comes via xx1 or the new x01? That is if the spider is removable and is the same spline pattern as former x9 cranks? under 50$ for an alu ring and I was thinkinging this was the direction to go with on my new beargrease.

    Any reason this would not work?

  13. I am looking to use a 29T alu ring from on my new X9 Beargrease. The idea being that I could go with a 29 in the front and use the 10spd gearing that comes with the bike to get a suitable ranged 1×10 drivetrain and to avoid the fuss of the xx1 or xo1 hub/crank issues. Basically and 50$ ring to get the job done… but the ??

    Is the spline pattern on this crankset different than the other x9 cranks and also is it removable?

    Logic would say it’s the same to keep manufacturing costs down….but just want to be certain this would work before I order then ring.


What do you think?