The Shimano Deore M6130 12 Speed 56.5mm Chainset features forged crank arms that remain rigid whilst being incredibly strong and durable. The HollowTech II integrated bottom bracket design uses a wide bearing placement with a large axle diameter for increased stiffness, efficiency and added durability. Shimano Deore M6130 12 Speed 56.5mm Chainset Features Lightweight aluminium chainring We recommend that the bottom bracket is initially installed by a bike shop to ensure perfect facing and fit 56.5 mm chain line for use with 157 mm O.L.D. frames Direct mount chain ring 12-speed Dyna-Sys compatible