Altus FC-M311 cranksets feature aluminum crankarms with steel SG-X chainrings for smooth and reliable shifting. Hyperdrive integrated SG-X steel chainrings provide precise and reliable front shifting. Proven 3-pc. design with sturdy aluminum crank arms (bottom bracket sold separately). 50mm Chainline / 187.9mm Q-factor. Item Specifications: Color: Black, Rings: 48/38/28, Number of Chainrings: Triple, Crank Length (mm): 170, Crank Intended Use: Mountain, Drivetrain Speeds: 7, Drivetrain Speeds: 8, BB Included: No, Pedal Spindle: 9/16", Spindle Interface Type: Square Taper JIS, Chainring BCD: Riveted, Chainline/Hub Compatibility: 135/142 MTB Hubs, Defined Color: Black,