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Project Fatbike Review: e*thirteen’s XCX+ Fatbike Crank

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Project Fatbike Review: e*thirteen's XCX+ Fatbike Crank

It wasn’t that long ago that 100mm wide fatbike specific cranks were fairly hard to come by. e*thirteen by the hive was one of the first few companies to take a chance with an external bearing crankset designed specifically for fatbikes. When it came time to build up Project Fatbike, it was an easy choice – though there was no shortage of negative comments about the cranks on other sites. To see if the comments held any water, we tested these for two full seasons deliberately trying to put them through the worst conditions possible to form our own opinions.

See how the XCX+ fatbike cranks survived, next.

Project Fatbike Review: e*thirteen's XCX+ Fatbike Crank Project Fatbike Review: e*thirteen's XCX+ Fatbike Crank

Weighing in at 791g for the crankset and 85g  for the bottom bracket, the 876g total package (minus a few plastic shims) is pretty impressive, especially for a triple fatbike crank. Built with a 145mm long spindle and e thirteen’s P3 Connect Spindle Interface, users are able to stuff a 30mm diameter spindle into a standard frame with threaded BB cups.

Project Fatbike Review: e*thirteen's XCX+ Fatbike Crank

The bottom bracket then of course requires a special tool, though fortunately it is included with the crankset. Smartly, the tool fits inside the standard Hollow Tech II bottom bracket tool to use with a torque wrench, or in a pinch can be used with an 8mm allen wrench.

Project Fatbike Review: e*thirteen's XCX+ Fatbike Crank

Here’s where things probably go wrong for all of those people with negative comments on the cranks – BB installation. As is all too common, it’s easy to toss the directions thinking you’ve installed plenty of bottom brackets and you don’t need no stinking directions. However, thanks to how sensitive the BB can be to one shim too few, or too many – following the instructions to a “t” is imperative.

Fortunately, for their new TRS cranks, the shim system has been replaced by their APS bearing adjuster which is similar to the old XTR-M970.

Project Fatbike Review: e*thirteen's XCX+ Fatbike Crank

With all of that said, after following the directions carefully, and taking my time (and torquing everything to spec) – the end result was perfect bearing adjustment without a hint of play for almost two years now. The cranks have never loosened up, made any creaks, and have been completely trouble free the entire time. When the BB didn’t look like the photo above, it was being soaked in salt spray on the back of the car driving to the trail. Short of submerging it in salt water for an extended period, the XCX+ crank and BB were put to the test and emerged unscathed.

Project Fatbike Review: e*thirteen's XCX+ Fatbike Crank

Performance wise, it’s incredibly difficult to judge the stiffness of a crankset while it’s mounted on a bike with 4 inch wide, squishy tires – however, there was certainly zero noticeable flex. In the first half of testing I used it as a triple and the shifting with a Shimano Dynasys 10 speed chain and XT M770 shifter and front derailleur was quick and crisp even at the slow speeds typically associated with fatbikes.

Eventually I wanted to make the bike lighter and ditched the whole front derailleur set up in favor of a 1×10 drivetrain. Really my only complaint with the XCX+ comes from removing the small ring since it uses Torx bolts. Normally it wouldn’t be a problem, but since the spindle is 145mm, all of my Torx wrenches hit the spindle preventing full rotations. It’s a very small issue, that just causes you to have to work slowly in small rotations to remove the ring – though an allen bolt would allow you to use a ball end wrench which would work much better. Using the stock 32t ring and hardware, I was able to make it single speed with the addition of 4 chainring bolt spacers, although single ring chainring bolts would work as well. Future upgrades include testing out some new narrow-wide chainrings to get rid of my functional – but ghetto, chain tensioner.


  • Lightweight, stiff
  • Triple or single ring compatible
  • Durable to the elements if set up properly
  • Finish held up admirably to boots scuffing the arms with wider fatbike q-Factor


  • Bottom bracket shim system is time consuming, and tricky to set up (though some cranks now have much better APS system)
  • Torx bolts on small chain ring are annoying (briefly)


The e*thirteen XCX+ fatbike crank is an excellent choice for a lightweight upgrade to any big tired bike, though you have to pay special attention to the install. A few extra minutes (or hour) spent in the work shop will yield perfect results on the trails if done right. The fatbike crankset market is starting to get crowded, though e*thirteen has proven they’ve been a contender since the early days.

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10 years ago

I’ve used these cranks for two years. I set them up to spec and they’ve worked pretty well. However the bottom bracket does get contaminated when I’ve ridden in wet and let it sit. After smacking it with my foot to break the initial bond it does loosen back up. However, I don’t think the rumbling that the bearings make is to spec. For me I think this would be a wonderful crank if they sealed the bearings better. I’ve also seen a friend’s crank that had one of the bearings completely seperate when the crank was removed. I can’t vouch for that one being set up correctly.

10 years ago

I had bearing problems in the beginning too, but E13 hooked me up with a new bb without issue. My big problem with the crank (on a non fat bike) is the sharp machining on the crank. It can cause some nasty ankle gouges.

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