Certain competitors of Shimano have demonstrated the market's demand for a twelve speed mountain drivetrain, and no wonder: there are seemingly endless options for soaring up every steep, while retaining power-packing options for the flats and steeps. Being the keen observers of the industry they are, then, the company has released the Shimano XTR FC-M9100-1 Crankarms, along with its all-new XTR M9100 12-speed groupset. The new XTR M9100 crank arms do not deviate enormously 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 (not included). The Shimano XTR FC-M9100-1 Crankarms are available from 165mm to 175mm lengths, offering options that cater to the shorter riders. The system is designed specifically for M9100 chainrings, which are available in both one-by and two-by configurations to suit your riding needs. 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 may mean reaching the finish line first. The cross-country minded 9100 version of the M9100 crankset features a 162mm-wide Q-factor -- narrower than the 168mm all-mountain M9120 version -- which boosts pedaling efficiency for racers, and ads a little extra width over previous 9000-series cranks to expand compatibility to more rides.