New four arm chainring design Optimal balance between stiffness and light weight Hollowtech-II (HT2): integrated bottom bracket spindle with right crank for increased rigidity while left arm mounts to splined spindle Aluminum construction with anodized finish provides strength, weight savings, and keeps the crankset looking great Gear shape optimized for HG-X chains Compatible with HG-X 10-speed chain 43.5mm Chainline 150mm Q-factor Chainline/Hub Compatibility: 130 Hubs , 135/142 Road Disc Hubs > 415 mm Chainstay Pedal Spindle: 9/16" Crank Intended Use: Road Rings: choose; 48/34t, 50/34t, or 52/36t Spindle Interface Type: Shimano Hollowtech II Drivetrain Speeds: 10 Chainring Bolt Circle Diameter: 110mm Shimano Asymmetric BB Included: No (sold separately)