- 12 speed Record / Super Record chainring - Surface treatment improves durability - 145 BCD outer rings are specific to Record or Super Record, while 112 BCD inner rings are shared between the two groups

The Shimano R9100 series crankset achieves the ultimate in optimal power transfer. It does this through a more reinforced outer chainring on its unique asymmetrical four-arm spider construction. - Chainring BCD: 110 Shimano Asymmetric - Drivetrain Speeds: 11 - Material: Aluminum - Ring Position/Type: Outer