FRONT CHAINWHEEL, FC-M5100-1, DEORE, FOR REAR 10/11-SPEED Series: Deore Generation: M5100 Crank Arm Length: 170mm Chain Ring Combination: 30T Bolt Circle Diameter: 96mm asymmetric Bolts: 4 Chain Ring Material: Steel Crank Axle Material: Steel Crank Arm Material: Aluminum Compatible Chain: HG-X11|11-speed|-|HG-X|10-speed Bottom bracket sold separately