A high performance chainset from the classic ATB group, offering the most advanced features Forged HollowTech II aluminium cranks offer unrivalled strength-to-weight ratio Lightweight construction with external super smooth bottom bracket bearings for efficient use Drilled steel and carbon composite construction middle ring combined with a thicker aluminium double anodized 44 tooth, and plated aluminium 22 tooth ring for excellent rigidity and durability SG-X chainringsdelivering a smooth precise shift and are Hyperdrive compatible Stiffness and strength increased with advanced design due to wider spaced bearings and oversized axle 44 / 32 / 22 tooth 9-speed chainrings We recommend that this bottom bracket is initially installed by a bike shop to ensure perfect bottom bracket facing and fit Comes complete with bottom bracket for 68 and 73 mm frames Weight: 853 grams for M770 in 175 mm