Great value Deore M6100 2-piece design chainset for 12-speed Dyna-Sys MTB HG-X transmissions Forged crank arms rigid whilst being incredibly strong and durable HollowTech II integrated bottom bracket design uses a wide bearing placement with a large axle diameter for increased stiffness, efficiency and added durability Lightweight aluminium chainring We recommend that the bottom bracket is initially installed by a bike shop to ensure perfect facing and fit 52 mm chain line for use with 135 /142 mm O.L.D. frames Direct mount chain ring 12-speed Dyna-Sys compatible