Great value Deore M5100 2-piece design chainset for 11-speed MTB 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 SG-X chainring with patented spike pins give smooth and fast gear shifts under load We recommend that the bottom bracket is initially installed by a bike shop to ensure perfect facing and fit 51.8 mm chain line for use with 148 mm O.L.D. frames 11-speed compatible