The SHIMANO Ultegra FC-R8100 52-tooth outer chainring (official Shimano part number Y0NG98020) is a genuine replacement part engineered for 12-speed Shimano Ultegra Di2 road cranksets. Featuring HOLLOWGLIDE technology, its hollow-forged aluminum construction provides extreme torsional stiffness to maximize power transfer while keeping overall weight to an absolute minimum....

The SHIMANO 105 FC-R7100 50-tooth outer chainring (official Shimano part number Y0RS98010) is a genuine replacement part engineered for 12-speed Shimano 105 Di2 and mechanical road cranksets. Constructed from anodized aluminum with a rigid, hollowed profile design, it delivers exceptional torsional stiffness for maximum power transfer while keeping weight low. Featuring precision-engineered...