Exclusive: Shimano XTR gets 12-speed for 1x / single chainring with two cassette options and more… good for gravel?

Hot off the press from a reliable source (as in a good mate of JOM’s), we’ve learned the following:

  • Shimano is close to releasing XTR 12-speed for their 1x / single chainring drivetrains, known as CS-M9100-12.
  • Two cassette ratios to start with. 10-12-14-16-18-21-24-28-32-36-40-45T and 10-12-14-16-18-21-24-28-33-39-45-51T. 51 teeth!
  • Other details include direct mount chainrings and a new freehub body design – no firm details on these items, but one has to wonder, yet another cassette body standard?
  • This one may not appeal to the gravel bike crowd, but flat-mount XC disc brakes.

XTR is an MTB group, but in the past, at least for the Di2 version, the rear derailleur works nicely with the road hydraulic brake levers / shifters.

Finally, the following chart from Shimano shows details of the new cassette options.

shimano xtr 12 speed cs-9100-12

Draw your own conclusions and feel free to comment below.

Thanks for reading!

14 Comments

  1. Avatar Mike M

    Its about time Shimano! I’ve been running SRAM XX1 Eagle on my hardtail, full suspension, and the fat bike for over a year. The SRAM 12 speed is fantastic. I have the XTR Di2 on the gravel bike. The 11speed jumps are cog size is noticeable. 12spds would help to make that less noticeable. I’d like the 10-45 on the gravel bike!

  2. Avatar Dean Wette

    I’m running Force 1 42 x 10-42. I’m holding out for Force 1 Eagle eTap. ?

  3. Avatar TimG

    Better several years late than never;) This is cool but definitely more for actual mountain biking.
    A 10-50/51 cassette, even with 12 speeds, is a bit much for gravel riding. The jumps betwee gears are just too large. It seems a 12 speed 10-36 or 10-42 would be ideal as this would tighten the gaps between gears. Combine that with using a smaller chainring for 1x and you’d have a very good useful range. The majority of riders, myself included, never use the bottom 2-3 gears of their cassette in a actual gravel race, the terrain is simply never fast enough to spin out a 40-46t ring with 10t or 11t cog. Reducing the chainring size and tightening up the cassette seems more logical.
    Yes, I’d agree they will have a new freehub body standard with this because you can be certain Shimano will not use Sram’s XD/XD-R standard.

  4. Avatar souleur

    interesting, the 10-51, in that not sure how functional that is nor the weight factor having a single ring up from but slapping 2 others in the rear that are bigger

    the 10-42 is probably IMHO most usable with the right ring up front

    agree, that the space between gears would be fairly enormous for the 10-51 if you had a descent ring up front, but then if you go to small, good night, you could climb a tree with a small ring/51

    just give me a donut, to eat rather than pop it on the rear cog

    the rear derailleur is what I am anxious to see more than the rest, it must be something

  5. Avatar Dean Wette

    I think a 12-speed 10-42 should be just about right for gravel. I have an Absolute Black 42T up front and have managed to climb pretty steep grades (18%+) with the 10-42 (XX1 11-sp cassette) I have now. If I need to I can go with a 40T ring. I probably wouldn’t miss the tall end of the gearing I have now.

  6. Avatar Chader

    Some comments about 10-42 and the 10-51 seem to miss the new possible “sweet spot” 10-45 cassette. It could be the happy medium for allowing a front ring to give reasonable top end while still preserving some low speed climbing for those with steep and extended hills.

    • Avatar Dean Wette

      I noticed they introduced a 10-45 & gave it brief thought, I’m just not so sure I would need it. My 42 x 10-42 has served me well, and I haven’t walked up a climb yet. OTOH, if SRAM does a 10-45 Eagle I may give that some consideration.

  7. Avatar @MrRichardH

    I welcome this with open arms (I mostly ride mountain bikes, very slowly ;-). ) with just a couple of reservations. 10-51 feels like a brazen attempt to out-gear-inch SRAM’s 10-50 Eagle cassettes. “We offer 510%” Shimano can say as Eagle offers a 500% range. Also, this is XTR only, so it won’t be cheap. SRAM offer Eagle at a (roughly) XT price point with the GX kit. I look forward to seeing the kit though. Competition is good!

  8. Avatar John uy

    What do you mean by shot/shot-ni
    Tbd

  9. Avatar souleur

    so….why are our gravel bikes/gear becoming more like mtn bikes???

    perhaps off topic, or a new topic
    -suspension up front
    -in rear now too
    -teeny weenie front rings
    -big cookie 51t rear cogs
    -large volume hookless beaded now wheels and very wide rims

    I mean, is it that simple to just put a drop bar on a full suspension mtn bike and call it gravel or is indeed different???

    do we need it or is this a marketing scheme we are just buying hook line and sinker?

    • Avatar Brad Comis

      “so….why are our gravel bikes/gear becoming more like mtn bikes???

      perhaps off topic, or a new topic
      -suspension up front
      -in rear now too
      -teeny weenie front rings
      -big cookie 51t rear cogs
      -large volume hookless beaded now wheels and very wide rims

      I mean, is it that simple to just put a drop bar on a full suspension mtn bike and call it gravel or is indeed different???

      do we need it or is this a marketing scheme we are just buying hook line and sinker?”

      Do you want to ride a bike on Asphalt/Gravel with a 67* headtube angle and a 40mm stem? The geometry is what makes a gravel bike a gravel bike and not a mountain bike. The drivetrain and wheels are just parts hanging on the frame.

  10. Avatar John

    I’m thinking that 10-45 cassette would be perfect for gravel. Similar gear range to a compact with an 11-32 cassette, and better jumps between cogs than the current Shimano XT 11-46 cassette with that weird bailout gear at the low end.

    The problems are that (a) there are no mechanical brifters yet for the new 12-speed pull ratios and (b) there’s also no Di2 12-speed rear derailleur announced, so there’s no way to set this up with what we’ve seen so far.

    • Avatar John

      I almost forgot, we also don’t have compatible Hyperglide+ chainrings to mate up with the new chain design. The Shimano MTB single chainrings will max out at 38T, which is about right for a mountain bike but bordering on too small for 1x gravel.

  11. Progress…

    A new cassette standard that allows for 10 tooth without expensive to manufacture cassettes with rear threading, it might be a tad hard to swallow at first but think in short time will be seen as a good step. 10 tooth is a good edition to the enviroment and think this iteration will be more quickly adopted to an industry standard.

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