Great value Deore HollowTech II design chainset for 10-speed Dyna-Sys MTB HG-X transmissionsThe HollowTech II Chainset features hollow forged crank arms which are both lightweight and rigid whilst being incredibly strong and durableHollowTech II integrated bottom bracket design uses a wide bearing placement with a large axle diameter for increased stiffness, efficiency and added durabilitySG-X chainring with patented spike pins give smooth and fast gear shifts under loadLightweight aluminium outer with steel/glass fibre composite inner chainringWe recommend that the bottom bracket is initially installed by a bike shop to ensure perfect facing and fit51.8 mm chain line for use with Boost 148 mm O.L.D. frames96 / 64 mm bolt circle diameter10-speed Dyna-Sys compatible