Shimano usually isn't the first to market when it comes to new product segments, but their engineers and craftsman pretty much always hit the nail on the head when it comes to performance and reliability. The XTR XTR FC-M9120-1 Boost 1x Crankset is designed to pair with their new XTR 12-speed drivetrain, and it features a lighter and stiffer design that now uses direct-mount chainrings with a single key release, allowing you to easily customize your new 12-speed configuration to find the perfect gear ratio for your terrain and riding style. If you're a little confused by Shimano's offerings of both the FC-M9120 and FC-M9100 cranksets, you're not alone. With two offerings in this top-tier package, the differences may be difficult to spot at first glance. Shimano builds the M9120 with a beefier, more robust design than the XC-oriented 9100, ideal for aggressive trail and enduro riders charging hard and having up-close-and-personal encounters with rowdy sections of trail that give your crankarm the occasional bash. On top of the beefier construction, the M9120 crankarms boast a wider Q-factor that lands in at 168mm, in comparison to the 162mm of the 9100. This wider Q-factor increases stability when you're descending at high speeds, and offers a bit more chainstay clearance for the beefier chainstays found on modern all-mountain and enduro bikes. As its name suggests, this particular XTR M9120 Crankset is intended solely for bikes with Boost 148-millimeter rear axles, with its 52-millimeter chain line reflecting the outboard move to accommodate Boost axle spacing. The crank arms come with your choice of 30t, 32t, or 34t chainrings, and can easily be converted between a single-ring and double-ring setup in order to best suit your riding needs. Additionally, we sell the XTR 9120 cranks in both 170mm and 175mm lengths, so shorter riders, or those with gravity-oriented appetites who want a little more clearance, can be decked out with the perfect crank length, too.