Shimano Altus 7/8SPD Square Crankset The Shimano Altus line is Shimano's budget friendly mountain groupset, bringing time-tested Shimano quality to the entry-level cyclist. The Shimano Altus 7/8SPD Square Crankset is an excellent replacement crank for entry-level bikes. Shimano Altus 7/8SPD Square Crankset Specifications Bottom Bracket Not Included Arm Length: 170mm, 175mm Spindle Interface Type: Square Taper JIS Spindle Length: 123. 0 mm Chainring BCD: Riveted Crank-FD Type: Mountain Triple Chain Compatibility: 3/32" Pedal Spindle: 9/16" | Shimano | Altus Fc-M311 Crankset | Black | 170Mm, 22X32X42T | Aluminum