The SRAM Red E1 groupset is SRAM’s lightest electronic disc brake groupset ever. With revisions to the shifters and brakes, it may also be the most ergonomic, and quickest braking electronic groupset ever. The SRAM Red E1 Crank Arm is an exceptional base for building your custom crankset, swapping to a shorter crank arm length, or upgrading your SRAM crankset.