SRAM XX1 Drivetrain

Each individual component in the XX1 build kit has been optimized specifically for single-ring use. At every stop on the component checklist, I found a well thought-out and executed component that worked very well for the application.


The derailleur of the XX1 works a bit differently than other derailleurs. Since it is not designed to work with multiple front chainrings, the derailleur only needs to move horizontally along the cassette. A traditional derailleur moves diagonally—both sideways and fore-aft—so that it can accommodate both the chain slack as you move through the cassette, as well as the chain slack as you change rings in the front.

Sram XX1 Derailleur, Blister Gear Review
Sram XX1 X-Horizon Derailleur

I do not have more than anecdotal evidence that this translates to a more durable rear derailleur, but I have smacked the XX1 into rocks a number of times now, one of which I believe would have bent every single other derailleur I have ever ridden, and the XX1 has escaped without damage.

My theory is that a traditional derailleur will twist easier than the XX1 with a direct, sideways rock hit, because as a traditional derailleur is being pushed in, it is also being prevented by the rock from moving forward, causing the derailleur to twist fairly easily.

With the XX1, the rock just pushes it in, and the derailleur returns to its place without incident. In other words, unlike a traditional derailleur, the hit does not prevent the XX1 from achieving its regular travel. So no big deal.


The new XX1 11-speed chain features hollow pins and cutout chain plates to keep it light. It is also very thin: 0.5mm narrower than a 10-speed chain.

I have not had any issues with the narrow chain, but it is important to note that if you wind up needing to add a link or two, the hollow pins on the chain do not press in and out. If you cut the chain, I would strongly suggest using a SRAM quick-link to put the chain back together instead of pressing the hollow pin back into the chain. If you do, it’ll break when you go ride.


The shifter is, in essence, an updated SRAM XX shifter with 11 shifting detents. It is very smooth and positive in feel, in contrast to the light and vague feel from the XT shifter that it replaced.

The XX1 shifter also has a pretty wide adjustment range to its barrel adjuster, which I appreciated since it helps to keep the shifting tight as the cable stretches through use.

Cranks and Spider

The XX1 crank is offered in three lengths (165mm, 170mm, 175mm) and two Q factors (156, 168). (“Q factor” is the distance from the inside of the pedal to the center-line of the frame—basically, how wide the cranks are.)

Sram XX1 Crankset, Blister Gear Review
Sram XX1 Crankset

The 168mm Q factor is the standard width for most modern full-suspension bikes, while the 156 Q factor approximates a road bike width.

The narrower 156mm Q factor provides a slightly more efficient pedal stroke, but you may run into clearance issues with some 29’er frames with short chainstays or boxy full-suspension designs.

The 168 Q factor will feel slightly more stable and planted while descending relative to the narrower cranks.

I elected to run the 168 Q factor in the 175mm crank arm length.

The XX1 crank arms are, as far as I can tell, the same as the SRAM XO cranks, just with a different spider and chainring. It is worth noting that the XX1 spider and chainrings are available separately, so if you happen to have a SRAM crank with a removable spider, you can set it up with the XX1 gearing on the front.

Additionally, the XX1 chainring is compatible with 10-speed drivetrains, so you can easily stick a XX1 crank or chainring on their 10-speed setup if you wish.


Perhaps the biggest story with XX1 (outside of its massive gear range) is the wide-narrow chainring profile. When you look at a chain, there are wider sections interlinked with narrower sections:

Sram XX1 HollowPin Chain, Blister Gear Review
Sram XX1 HollowPin Chain, with alternating wider and narrower sections.

SRAM has mated the chainring to match these alternating wide-narrow buddies in an effort to add chain retention on the ring. And this they have definitely succeeded in doing.

Just pulling the chain off the crank when removing the crank from the bike requires a good bit more attention. The first three times I tried to slide the chain off the ring, without paying close attention, the chain popped right back onto the ring rather than easily falling off as it would on a normal single-speed chainring. I had to actually think about what I was doing to make the chain come off. It really does work.

So far I have run the XX1 with and without a DH-spec MRP G3 chain guide. I have not dropped the chain without a guide, though the highest speed / roughest trails in the Wasatch have yet to open.

But given that the bike I have set up with XX1 is also equipped with a 180mm coil-sprung fork, 8” DH brakes, and will see near-daily use at the local shuttles and lift access DH trails, I will probably leave the chain guide on all summer just for peace of mind. But for fast trail riding on a ~160mm travel bike, I really don’t feel that a chain guide is required.

XX1 Chainring, Blister Gear Review
Sram XX1 Chainring

In short, the chainring design just works. Really, it works well enough that my guess is within one to two years every single chainring designed for single ring use will follow SRAM’s lead and feature wide-narrow teeth. The only limitation to the wide-narrow chainring is that it requires an even number of teeth. No 33t rings. C’est la vie.

16 comments on “SRAM XX1 Drivetrain”

  1. nice review professor-

    how about a 500 word essay on that roam? thing has been catching my eye more than kate upton doin’ the harlem shake…..

    • hey man, have to say that i am really happy with the roam thus far. it, at the very least, is a very solid trail bike. goes, stops, jumps. does all that jazz very well. the DH park is just opening up this weekend, so once i can put a bunch of laps on it there i will be prepping a real review, but super happy with it thus far.

  2. off topic again- but gear geaky all the same

    how would you consider it rating as a smaller sibling to a park bike? -or in other words as a dh’rs 30 ish lb do everything trailbike? does it compare to a spitfire or knolly endo for trailability?

    • hey mb-

      you are describing me, indeed. my build is about 32lbs right now with the ROAM, but that includes a 66 evo fork and 8″ saint breaks, so figure about 30 with a lyrik and 6″ xtr trails.

      the frame is every bit as stiff laterally as my old TR250, and significantly more stiff than a stump jumper or some trail bike. it descends corners more like a park bike / free ride bike than an xc bike. I would think its pretty similar to a knolly chilcotin in that regard. I would say the ROAM pedals better and is way more fun descending than the OG endorphin. i have not ridden a new endorphin though, but i attribute that to the high-ish single pivot that the ROAM utilizes. the wheelpath is fairly rearward due to the pivot location, so the wheel does not hang up, but the chain line is straight thru the pivot, so it pedals very well.

      there just isn’t much in SLC to justify a full blast DH bike unless you are looking to drive a couple hours, but there is plenty of rough high speed riding that a 160mm bike feels at home in. the ROAM is perfect for this.

      hope that helps?

  3. Great write up. Thinking my new ride may be 1 x 11. I have dabbled with 2 x10 on my wife’s bike but have been 3 x 9 for years. How big a deal is the transition from the 10 tooth across the cassette to 42, thinking the transition from hi speed through a depression (stream or what not) to steep up? Filling out order form, XT 3 x 10 or XO 1 x 11, expecting I’ll be real happy regardless.

    • hey jim,

      it takes 3 pushes of the thumb while soft pedaling to get from a tall descending gear to a hill climbing gear. with a 3x setup, you would need to shift down 2 clicks in the front ring, and probably 2 or more thumb pushes to the rear derailleur to get to a hill climbing gear… so yeah, i would take the 1x setup all day long here.

      hope that helps?

  4. Marshal, really great review of this thanks so much. best info out there on the XX1. I’ll order one to replace my 1×10 on cross country hardtail [21lbs]. I was cracking on the long steep climbs and race situations and had resigned myself to 2×10.

    • nice nigel,

      I feel fairly confident that you would be quite happy with the range that the XX1 (and pending X01) groups offer. also of note that while the XX1 crank and ring are exceptional, they are not required, per se, and you can easily run the setup with your existing 1x setup without issue.

      thanks and all the best!

  5. Funny that all the comments here seem to reveal that we were all led by the frame :)

    I’ll add another – still planning a review of that Roam? Now that you’ve had more time on it and hopefully logged several thousand feet at the Park as well as trail time, I’m curious how you’re liking it and how it compares for trail/park.

    I’m currently on a Mojo HD, which works well, but 1) feels over built for a lot of trail riding 2) does a horrible job at small bump compliance – especially at the DH park, 3) can’t convert to 275 without losing travel, 4) but is a dream to jump and pedal. Not quite burley, but not quite racy. Considering the Roam as a better option for the burly trails and all day at the park where I rarely need a real DH bike (I ride CO mostly)

  6. I’m riding a new bike with XX1 and have a few days in with a 32t up front. In Fernie BC the rides are most often grinds to the top, preferably technical followed by a technical downhill. Maybe its just my 43 years but generally I find if my eyes are tearing I don’t need to shift to a small cog and accellerate. That being said I spend most of my time in the bigger cogs on the casette on the up and just use the smaller ones for that momentum boost on the dowhill to keep the pump. So now the point. I’m considering going down to a 28t up front not because I lack the legs but more so to keep the chain in the center of the casette for more of its use. Since I never use the bottom two cogs now this move would drop one “shift” and I’ll probably climb more in the 36t cog and use the 42t as a bail out. I am concerned even with a new bike about the extreme angles chain makes and the resulting wear on the ring, chain, and casette, both of which are pricey. Any comments on the durability over time and which cogs are the ones that give up? I’m betting its the 42t.

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