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.
SM-CRM70 chainring teeth (not included) are compatible and feature Shimano's new Dynamic Chain Engagement technology offering enhanced chain retention, driving rigidity and highly efficient. This crankset has a 50mm single ring chain line for use in conjunction with 135/142 mm O.L.D. We recommend that the bottom bracket is initially installed by a bike shop to ensure perfect facing and fit.