SRAM XX1 1x10 mountain bike group for endurance and XC racers unveiled

SRAM will be releasing a new 1×11 system for endurance racers called SRAM XX1.

Built around a single chainring in the front, it gets a new “widest available range” cassette and will incorporate their Type 2 chain management. The rear is 11 speed, they’re noting it’ll work with both trigger and Grip Shift. The system will officially debut at Crankworx Les 2 Alpes on July 9-15.

Details are a scant at the moment, but there are a few things we can tell from the photos. First, that’s definitely a prototype rear derailleur, and the crank arm is two-piece rather than XX’s one piece. If we were betting folk, we’d say the final version might very well be a one-piece crank/spider given that it’s at the XX level. If so, and if it is designed around carrying a single ring, could drop a minimum of 30-40g off the existing set up just at the crankset.

UPDATE: Yep, it’s 11 speeds (better image of cassette added below), which should make it a good fit for the 2013 DT Swiss wheel and hub range, which all move to an 11-speed spacing. (Thanks to everyone that caught that!)

That weight would likely be made up with the addition of the Type 2 clutch mechanism on the rear derailleur, but, if that system negates the need for a front chain guide, the drivetrain ends up being about the same weight…save for maybe a few grams from the monstrously larger big cog on the cassette…

SRAM introduces 11-speed rear cassette for mountain bikes

Count ’em: SRAM cranks it up to 11! And as suspected, it mounts up just fine (apparently) to Mavic’s wider freehub body.

UPDATE: If we’re all counting correctly, it’s a 10-42 cassette. No lock ring is visible on the smallest cog, which indicates it is the lock ring. Also looks like the derailleur is bolted onto a direct mount-like “B-Link”. Notice how the cable enters on the inside and appears to come out the outside, making for a potentially interesting pull direction, especially with the parallelograms looking almost parallel to the cogs.

SRAM XX1 1x10 mountain bike group for endurance and XC racers unveiled

Where the overall system weight savings (and gain in simplicity) comes is with the lack of a front derailleur and shifter. Shedding those components would yield at least a 130-150g savings.

One interesting tid bit we’re trying to get more info on is the thicker teeth on the chainring. Every other tooth is dramatically bulkier. Could be a noise dampening design? We’ve got calls and emails in to SRAM.

SRAM XX1 1x10 mountain bike group for endurance and XC racers unveiled

The rear derailleur has a very long cage, necessary for the oversized cassette. This prototype has a pretty stout lower parallelogram arm and *gasp* an Avid Rollamajig! We’re just guessing here, but compared to the current 11-36 XX cassette I’ve got on my bike, this one looks like perhaps a 40T big cog…meaning you could potentially have a 1:1 or less ratio!

It’ll be interesting to see if they can put such a massive cog on there and still use the machined out design of the current XX cassettes. More as we get it!

SRAM XX1 1x10 mountain bike group for endurance and XC racers unveiled

Looks like they’re doing testing on a Cannondale Jekyll, which is a 150mm travel all-mountain (sorry, Over mountain in Cannondale parlance) bike. If the Type 2 clutch system can keep the chain on without a guide for their pro riders, we’re guessing it’ll be pretty stable for the rest of us.


  1. Shane on

    I don’t understand where people have been so mis-informed about long/medium/short cage derailleurs. I see it over and over again and it irritates me.

    The length of the derailleur cage is dependent on the difference in teeth between the front and the rear. Here is the Calc: cap req’d (T) = (BIG ring – small ring) + (BIG cog – small cog)

    SRAM Mountain derailleurs have ratings as follows: long = 43T; medium = 37T; short = 30T

    A 42/28 x 36/11 will have a maximum tooth difference of 39 teeth, that would necessitate a Long cage rear derailleur.

    The assumed picture above I’d guess is 36T front with an 11/40 out back that equals 29 teeth, making the SHORT cage the best choice.

    • ZachOverholt on

      @shane, you are correct on cage sizing. However, since other sources are reporting rumors that this is a 10-42 (!) cassette, the medium cage is necessary, though not the long like you mention.

  2. Tyler (Editor) on

    All – good counting, thanks for the quick heads up on the cog count. Article updated with a few extra links about 11-speed hubs and spacing. Still waiting to hear back from SRAM on a few details.

  3. Ken on

    Is the 11th cog on the cassette body, or is the smallest gear a special lockring/cog? Smaller than 11T perhaps?

  4. Louis on

    For me, 11 cogs in the back makes a front derailleur even more worthless.

    Can’t wait to build up a 1×11 set up on a XC bike.

  5. craigsj on

    It’s good to see the wider gearing range, it’s the only reason to add more cogs to an MTB. I wish it came in a widely supported standard, though. With several efforts to expand range down to 9T, there’s a possibility of too many incompatible hub and cassette standards. I think a 10-42 would be great, but not if only one or two suppliers supported it.

  6. Todd on

    I would guess those fat chainring teeth are to keep the chain from jumping off. I love my 1×10 setup, but require an MRP Chainguide, which negates a lot of the “no front derailleur” weight savings. If they can figure out a way to keep the chain on a 1×10 setup without a guide, that would be light and clean solution. You don’t have to be bombing down a DH run, without the front guide you can drop your chain on a micro bump.

  7. Robert on

    Just moving the weight from the front to the back. All this extra weight out back only decreases the performance of the rear suspension. Unsprung weight is BAD!!!

  8. WV Cycling on

    Will the benefit of pushing/rotating that big of a cassette outweigh having two chainrings?

    Seriously, 42t rear?

    How about we shed weight overall, and go with a “Junior” style freehub, and get a 9-36 with a 30t chainring?

    25.6 – 102.3 gear inch spread. Close to a 400% change in development… 0.89 to 3.56 ratio.

  9. junkshow on

    It looks like the small cog is only 9 or 10 teeth. If it is this will probably not fit the DT 131 OLD hub (or any HG spline cassette body)

    New ultra mega-range cassette body shape?

  10. lou on


    they may not be able to fit a 9 speed cog,.maby they can, a 9-38 with a 29 up front would be a dream alround set up for me. then swap the 29 for a 32 for race days!

    hope had a prototype 9×1 speed with a small 9 on the cassette, maby the’ll pick up the ball and do a nice 11 speed 9-38.

  11. Biikkee on

    Junkshow is on the right track w/ the idea of smaller 9t cog. If they would use a 9t high gear, the low rear cassette cog would be smaller and the single front would be smaller to decrease the weight over all even more. However the durability on the 9t might not be up to par for long term… bet they are testing a 9t. Seems like the next logical step.

  12. Bazookasean on

    You can count fairly accurately in the pic. A couple of us all counted half the big cog at 21 (42 t) and half the small cog at 5 ( 10t ). That’s gonna be a huge advantage for most of the riding here in the Midwest.

  13. dave on

    wouldn’t the higher position of the chain on the biggest cogs affect the performance of the suspension? Seems like it would mean more compressive force.

  14. Nate on

    Wouldn’t any weight savings be more than negated by drivetrain efficiency losses with a setup like this?

    1) A 1xwhatever results in a poor chainline more often than a 2xwhatever or 3xwhatever.

    2) A 1xwhatever results in the use of smaller cogs more often than a 2xwhatever or 3xwhatever.

    3) A 1xwhatever, especially with a gear range this wide, results in the rider being in a less than optimal gear more often than a 2xwhatever or 3xwhatever.

    These factors will have a significant negative impact on drivetrain efficiency, probably up to 5% or so. I highly doubt that saving a couple hundred grams would have anything close to this effect.

    Having said that, I love 1x setups because of simplicity. But it seems to me like the price for that simplicity is efficiency.

  15. S W on

    If all the gears have an even number of teeth, could they match the wider chainring teeth the the wider links of the chain (outer plates) and thinner teeth to the narrower links? This could help keep the chain on the chainring too, since they have two types of teeth to fit the different width chain links… Maybe?

  16. greg on

    drivetrain efficiency goes down with cogs with less than 16teeth. 11tooth cogs=poo, 10tooth=pooier, 9tooth=pooiest. i sure hope sram’s not seriously trying to do a 10tooth cog. im not sure itll fit on a current freehub anyway.
    mavic mountain freehub bodies are not longer. their road ones are, as well as the ones on their cheapest mountain wheels.
    interesting derailleur, with its horizontal parallelogram and heavily offset upper pulley.

  17. Duder on

    I heard that Sram purchased Pacenti’s tri-lobe freehub body design to use as the proprietary mechanism for this system.

    The major detail they are not showing is that it will use Shimano’s new direct-mount RD standard

  18. Jay on

    I think maybe many of the roady’s and pure XC boys are missing the point of this drivetrain. For endro racing where you are doing multipul runs on various punishing DH courses, drivetrain efficiency goes out the window as you tend to be draging around very grippy tyres which are many time more inefficient the running a cross gear. The most important thing is reliability and a front mech is just a liability on real punishing trails. Although saying that the im not keen on the guidless singlering up front, no matter how crazy the tooth profile.

    One thing does arise in my mind tho is when a cassette gets so big and increases in weight, the disadvantages in weight of hub gears like alfine and rolholf is reduced and with there large range and simplified drive train there must be temptation to run one of these with a chain tesnioner.

  19. Art on

    I’m running a 2×9 currently but this would get me to ditch my front derailleur which I’ve always wanted to do and I want a sram clutch rear deraileur for noise reduction anyway so sign me up.
    current granny is 23/34 for 19.6″ gear
    current middle is 33/34 for 28.1″ gear
    I’d keep current middle ring and ditch the granny for 33/42 for 22.8 gear inches.
    I can live with that as it is about the same as the gear in one cog less than the biggest currently.

  20. Bazookasean on

    The front chainring is a good idea. If it never shifts in the front, the teeth can be designed to support the wider and narrower links to resist falling off in the ruff stuff.

  21. Bazookasean on

    *Duder. If you look at the pics on bikeradar it is not direct mount. The c’dale hanger just looks that way.

  22. Tom on

    They have been doing 1xwhatever setup for years on Downhill and Dual Slalom bikes. Time for XC bikes to “officially” get it. Innovative idea?…maybe a little but nothing worse than riding a trail without the proper selection of gearing.

  23. dhbomber on

    I don’t get this….while technology has to go somewhere, I don’t think this 1×11 makes sense. C’mon a 42t cog at the back? HOPE’s idea is a rad one! Was waiting for that to come out but I think they shelved it. Like WV says, it’s a 10 speed 9-36, or even 38, and just run a single front chainring. You have your new “clutch” rear der. technology, and can get away with not using chain guide. PLUS, HOPE’s approach to this eliminates a freehub body, thus saving a little bit more weight. This is just absurd.

  24. Brian on

    re: Todd- I’ve been running my XTR Shadow + without a chain guide and have not dropped a chain yet. The stock clutch setting was pretty low, so I cranked the tension up a little to add some extra stiffness and through very rough terrain (which is what I always ride) it’s been nice. I don’t suggest this course of action to everyone, but it works for me.

  25. Mark W. on

    what bike radar is missing the picture of the new free hub body needed to make the whole cassette system work, which is what really overall is the pushing boundaries part of this group. While i dont really want to run what looks like an aluminum chainring that is machined to fit on a free hub body, the idea that this system uses a new graduated free hub body is exactly what both road an mountain biking need.

    Good on sram for pushing the boundaries with this system, I think it would be cool to try it as a single ring set up on a road bike too

  26. Devin on

    Yeah, internally geared hubs are looking better and better. Just use a scary light rim and you’ll get a wash in the weight dept. Then you get gear range, no worries about losing your chain (no retention system? lost chain waiting to happen, different tooth profiles and all,) stiffer/better braced wheel and almost zero maintenance. Waaaaaaay better means to an end than this.

    Also, people don’t mistake your biggest cog for a pie-plate and laugh at you.

  27. Bill on

    I agree with Devin, but more on the gearbox end. i would like to see a lighter version of the pinion gear box or one that is totally integrated into a frame. Moving the majority of the weight to the rear means a less responsive rear over small chatter and also, how long do you really think the single front chainring will last as far as keeping the chain on over such a large range? Without a chainguide, I’d give it about one month of serious riding.

  28. Jones on

    I want a 2×11 for XC racing. Not because of some weight saving or anything but just to maximize the gear spread. Oh and while I’m pipe dreaming how about a return to the old days where you could go to your local bike shop and pick individual replacement cassette cogs off that blue board that Shimano had?

  29. (required) on

    How does 10-42 work with only 11 cogs? Do they have some 6-tooth gaps in there?

  30. djconnel on

    First, you forgot the weight savings from no front shift cable, housing. Add that to no front shifter, no front derailleur, and a missing cog and you’ve got a nice chunk.

    On the chain line: experiments have shown chain line is a small factor in drivetrain loss. Chainline is less of a factor with a mountain bike’s longer chain stays, in any case.


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