Making the call to switch to a 1x11 drivetrain isn't easy. Sure, 11 speeds kill it, but the change from 10 speed can also cost a whooooole lot of money, so it isn't always evident whether the upgrade is worth it. While SRAM's X01 BB30 Crank Arms aren't cheap, exactly, they're not as expensive as some other offerings, so they'll take a little bit of the sting out of a full 11 speed switcheroo. The most important feature of the XO1 Crank Arms is the material: pure carbon fiber. Thanks to carbon, the X01 tips the scales or not at just 655, when you take an X Sync chainring into account. That's a little confusing, though, because the crank arms come without a chainring, so you can fully customize you own setup with SRAM X01 or XX1 rings. To lock out dirt and reduce friction, the X01 uses SRAM's Gutter Seal design, and it comes with an aluminum spider for easy mounting and alignment.