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!

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

  1. 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. 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.

  3. 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

  4. 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.

  5. 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.

    1. 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.

  6. 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!

  7. 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?

    1. “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.

  8. 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.

    1. 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.

  9. 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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