The Shimano Deore XT M8100 Double 36/26 12 Speed 48.8mm Chainset uses forged HollowTech II aluminium cranks to offer unrivalled strength-to-weight ratio. Lightweight construction provides external super smooth bottom bracket bearings. This Shimano Deore XT Chainset is designed for use with 12-speed transmission systems. Shimano Deore XT M8100 Double 36/26 12 Speed 48.8mm Chainset Features 36/26T chainring combination 48.8 mm chain line for use with 142 mm rear axle width Stiffness and strength increased with advanced design due to wider spaced bearings and oversized axle 70 degree spider arm for optimal rigidity For use with 12-speed HG+ MTB chains only It is recommended that the bottom bracket is initially installed by a bike shop to ensure perfect bottom bracket facing and fit