Shimano's Deore XT M8100 12-Speed Single Crankset uses an entirely new construction, with exchangeable direct mount chainrings matched to their proven Hollowtech 2 bottom brackets (sold separately) to create a lightweight, strong and great value crankset.Forged HollowTech II aluminium cranks offer unrivalled strength-to-weight ratioLightweight construction for external super smooth bottom bracket bearingsFor use with 12-speed Dyna-Sys DCE single chainringsSM-CRM85 DCE chainrings are available in 28T, 30T, 32T, 34T and 36T52mm chain line for use with 142 / 148 mm rear axle widthStiffness and strength increased with advanced design due to wider spaced bearings and oversized axle70 degree spider arm for optimal rigidityFor use with 12-speed HG+ MTB chains onlyShimano recommend that the bottom bracket is initially installed by a bike shop to ensure perfect bottom bracket facing and fitThe Deore XT M8100 uses Shimano's long-standing Hollowtech II construction, giving you a crankset that is