Shimano Ultegra R8000 Crank Arm

Yes, this is a genuine replacement part designed specifically for the Shimano Ultegra R8000 series. It will integrate perfectly with your existing R8000 crankset, provided you match the crank arm length to your current setup.

This product is the crank arm itself. It typically does not include the crank arm fixing bolt or the plastic cap, so you should retain those from your original crank arm during the swap.

You can, but it is generally not recommended to mix crank arm lengths on a single bike. Using different lengths on the left and right sides will create an uneven pedal stroke and can lead to biomechanical issues or discomfort while riding.

You will need a Shimano Hollowtech II crank installation tool (often a plastic preload tool) to tighten the cap, and a 5mm Allen key to tighten the two pinch bolts on the crank arm.

While it uses the same Hollowtech II interface and may physically fit, it is designed specifically for the Ultegra R8000 aesthetic and weight profile. It is best to stick with the R8000 series to ensure optimal performance and a consistent look.