Great value Deore HollowTech II design chainset for 10-speed Dyna-Sys MTB HG-X transmissions. The HollowTech II chainset features hollow forged crank arms which are both lightweight and 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.