Shimano's XT Dyna Sys FC M785 Double Crankset crosses the line between a more limited one by gearing and a cumbersome 3x10 with gears you never use. Shimano is notorious for sending technology from its high end groupsets down the pipeline, and true to that mantra, the XT Hollowtech II crank arms receive the asymmetric design that is a marker of XTR. A 24mm hollow spindle is pressed into the right arm in the factory. Two pinch bolts secure the arm once the bearing preload is set. As far as the design of the chainrings themselves, the small ring is designed to move the chain up and then back down without slipping. When paired with the asymmetric chain, you'll never miss a beat.