SHIMANO XTR 9000 Race Mountain Bike Crankset - No Chainrings Hollowtech II design has an optimum balance of lightweight and stiffness for better power transfer and acceleration 3D hollow structure anodized aluminum crank arm for superior rigidity Chainrings not included Compatible with M9000 single chainrings (30T, 32T, 34T, 36T) and M9000 double chainrings (34-24T, 36-26T, 38-28T) Bottom bracket not included