Chainring sold separately Hollow forged crank maximizes power transfer while limiting weight Shimano's Hollowtech II technology provides the best balance of stiffness, strength, weight and rotating performance Features 52mm chainline designed for 142 or 148 Boost spacing 172mm Q-factor With loftier aspirations stretching into the drivetrain world, it was only a matter of time before Shimano entered the realm of 12-speed. It started with the sleek and racy 12-speed XTR group, but fortunately for those of us who are a little more budget conscious, it didn't take long for those changes to reach into the XT level groupset. Shimano's XT FC-M8100 1x Crankset takes the hollowcore tech you knew from years past, but switches things up to an all-new application with direct-mount chainrings, and a special tooth profile for improved chain retention, and 172mm q-factor for quick power and comfort in the saddle. The crank arms are crafted with Hollowtech II technology, balancing stiffness, strength, and weight for superior power transfer. Hollowtech uses cold-forging technology to create a light and hollow crank arm that doesn't compromise on stiffness, enabling you to charge hard into rowdy trail sections without worries of your crankset flexing under pressure, meanwhile the light weight keeps you from getting bogged down with extra grams when you're pushing for big mile days. Should you covet flexibility from lowland laps to days of ascents that tickle 5-digits, you'll appreciate the new direct-mount chainring application. The drive-side arm removes for ring placement, making chainring swaps easy to execute while your crank is still on your bike. This means you can toss on a lofty 34 or 36-tooth ring for smooth rolling singletrack, or give yourself a break with a 28-tooth when climbing is the day's main goal.