While Shimano is certainly a few years late to the 12-speed party, in typical Shimano fashion they've brought to the table a well-refined groupset that's ready to dominate come race day. Designed for cross-country racing and fast trail riding, the XTR FC-M9100-1 Boost 1x Crankset features lighter and stiffer crank arms, as well as direct-mount chainrings with a special tooth profile that greatly improves chain retention compared to the previous generation of XTR cranks. This particular crankset uses a 52mm chain line for bikes with 12 x 148mm Boost hub spacing, which is the standard that most mountain bikes are using these days. The new XTR M9100 crank arms are not vastly different from Shimano's consistently-proven formula of hollow-core alloy arms. Of note is the fact that the left-side crank arm is now hollow-bonded, a manufacturing process that saves weight over previous production methods without giving up strength. Where they do shift from older generations is in skipping the familiar spider and ring technology we saw in all preceding years, opting for a direct-mount application that enables the crank to be run as either a one-by or two-by setup. The spindle and arms themselves, without a bottom bracket, weigh a remarkably light 516 grams when paired with a 32-tooth chainring. We sell the Shimano XTR FC-M9100-1 Boost 1x Crankset in 170 and 175mm lengths with your choice of a 30t, 32t, or 34t chainring. Shimano crafts the crankset with its new 12-speed XTR 9100 groupset in mind, soaring into the new-age in which having a gear for every climb could mean reaching the finish line before your opponent. This is the cross-country minded version of the XTR crankset, featuring a 162mm-wide Q-factor that's narrower than the 168mm all-mountain M9120 version, boosting pedaling efficiency for racers, while at the same time adding a little extra width over previous 9000-series cranks to expand compatibility to more bike frames.