Long Term Review: SRAM XX1 1×11 Mountain Bike Drivetrain

Our long term test of SRAM’s XX1 group started in December with the weigh in of all parts, followed by some early impressions from Marc (which includes some great info on actual and comparable gearing ratios).

Now, after seven solid months of riding, including a punishing tromp through the Trans Sylvania Epic Mountain Bike Stage Race, we just as stoked on it as when we first got it dirty. And it’s still working just as well. Which is to say virtually flawlessly. Not only is the XX1 group quiet and smooth, but it’s rock solid. In seven months on two different frames, I’ve dropped the chain exactly once. And that was the result of a rapid endo that sent the bike flying sideways.

In addition to the darn near perfect performance, it’s also cleaned up the aesthetics of my bike. And it dropped a full half-pound from XX setup I had previously. Thinking about upgrading? Shift down for the full review…

DETAILS & INSTALL NOTES

With SRAM’s 2×10 mountain bike groups, their recommendation is to set the chain around the largest chainring and cog, then add two links. For XX1, they’re recommending wrapping it around chainring and largest cog then adding four links. You’re then adding the quick connect link, so technically this gives you five extra links of length. This small extra bit of chain allows for the massive range of the 10-42 cassette.

They say this gives you enough wiggle room to go between two different chainring sizes, but I managed to set it up around a 36t and drop all the way to a 32t chainring with no problems. The image above shows it with a 36t ring in the extreme ends of the cassette.

Note: On full suspension frames with noticeable chain growth, the chain should be measured at the point in sag where the chain is stretched the furthest. This might limit the range of chainrings you can use without adjusting chain length.

Installation is pretty straightforward. There’s no front derailleur to mess with, which saves a lot of time. A chiseled spacer takes the place of the inner chainring and provides a nice little resting place for the chain when necessary (or in the very rare event that it drops).

A built-in preload adjuster makes it easy to adjust bearing/crankset tightness. I’ve found that just twisting it until it’s finger tight works well, then lock it into place with the pinch bolt. The one downside is that it’s diameter creates potential interference with some bottom bracket designs. I’ve had a bit of trouble getting it to work with the new Wheels Manufacturing bottom bracket, but they’ve made it work on their bikes, so we’re still troubleshooting that one since it is working fine with an X0 crankset.

Both crankarms come with helicopter tape on the half closest to the spindle, which tends to be a heel rub contact area.

The rear derailleur uses a severly offset upper guide pulley. As the bottom of the cage is pulled forward, the pulley comes down, staying just below the gear it’s lined up with. Proper B-screw tension is key to making it work properly – just tension it until the pulley is far enough off the cassette to allow the chain to move freely between them. (Yes, the cassette can completely hide a 160mm rotor from view!)

Cable routing is smooth and clean, running around a large wheel and curved lever, around the bolt then straight out the front. Yes, I put a cable end on it before riding.

As the cable pulls, the parallelogram links move horizontally rather than at an angle. It’s the offset location of the guide pulley that brings the chain up or down in the vertical plane. The massive P-knuckle houses SRAM’s Type II roller clutch mechanism. Technically, it’s just a very strong retention spring since there’s no on/off switch, but we’ll go with the common nomenclature here. The Cage Lock seemed silly when it was first introduced, but having used it, it’s money.

The Driver Body and XX1 cassette are also amazing. They make cassette installation and, more importantly, removal super quick and easy. There’s no marring of the freehub body that causes cogs to get stuck in place – the whole thing slides on and off effortlessly.

The trigger shifters are virtually identical to the 10-speed models, offering adjustable positioning of the downshift lever.

From a technical standpoint, XX1 is impressive. It shows SRAM’s not afraid to change things up and do something differently if it means making a better product. I applaud their spirit of experimentation, especially when the results are this good. And I haven’t even gotten to the ride yet…

RIDE REVIEW & NOTES

The first thing you notice, after the weight loss of course, is how much cleaner the cockpit looks without a front shifter. Above is shown with a separate remotes for the fork and shock and Magura brakes.

Put together an entirely SRAM based drivetrain and brakeset, lose the rear shock remote, and things get beautifully sparse.

After registering for the TS Epic, I stocked up on an extra chain and a few extra 11-speed quick links, just in case. I’m happy to report that after seven months of riding all over, in mud, crud, dust and rocks (lots of rocks!), I have had a total of zero problems. No broken chains, no mis-shifts, no jams and, barring the aforementioned endo incident, no dropped chains.

Even when dirty, everything runs smooth…

…and quiet. The open design of the cassette coupled with the “silent pulley design” seems to work to minimize chain noise, and the clutch all but eliminates chain slap. It’s not until you get back on a bike without a clutch rear derailleur that you realize how much they help, and SRAM’s seems to be a bit stronger than Shimano’s without adding undue resistance to the shifting. Plus, not having an on/off switch reduces moving parts and, theoretically, improves durability. More importantly, it just means one less thing to think about.

Speaking of shifting, everyone has their preferences. I’ve ridden bikes with both drivetrain brands that had plenty of cable drag and bikes that felt like butter. Much of that has to do with quality of cables, housing and frame design and routing. I’ve been running my XX1 on two different Niner Jet9 RDO bikes, one with the original cable design and the newer one with continuous rear housing. The former has a curvy, tight bend in the housing between BB and chainstays and the latter, well, it has full length housing – both of which can be potential sources of drag. Fortunately, SRAM’s included cables and housing are very good, and I’m now running newer cables from Alligator that will be reviewed separately, so things have been smooth. Regarding the actual shifting action, SRAM’s levers have a much shorter throw than Shimano’s. Short enough that lazy shifting generally pays off just as well as intentional efforts. That means very quick shifts. The upshift lever is so quick that on bumpy terrain it’s easy to tap it two or three times by accident, but I’ll take that occasional inconvenience for the rapid, easy shifting. The downshift lever can throw the chain through four cogs with a full push but takes just a tiny bit of movement to sling up a cog.

SRAM’s Matchmaker mounting system helps keep things minimal and allows a small amount of fore/aft positioning of the lever. Combined with the two mounting positions on the lever body and the adjustment on the downshift trigger, it’s pretty easy to get things where you want them. The cable adjustment bezel is easy to turn even with full finger gloves.

I’ve worn through several layers of carbon on SRAM cranks before, so the protective tape is a welcome addition.

It’s showing scratches, but doesn’t appear to be wearing thin. A few flying rocks have made their mark on the crank arms, but it seems mostly superficial so far:

From a pure riding perspective, the XX1 has been flawless. The only downside is running out of gear (or having too much) when my days involved too many feet of elevation gain and loss. The only time that really actually mattered was during the TS Epic on a couple of the downhill fire road Enduro segments where I maxed out with a 32t but was wishing I had a 30t for the climbs. Other than that, smart selection of the two included chainrings means an entirely useable range of gearing with quickly swappable option for days away from normal trails.

I haven’t once missed my 2×10. I haven’t once thought “maybe I need a chainguide”. And not for one second have I thought about taking it off my bike.

Further reading:

• SRAM XX1 tech rundown
• Saris’ first impressions
• Marc’s first impressions
• Compatible hub manufacturers
• XX1 Actual weights
• XX1 official introduction
• SRAM.com