Innovative lightweight HollowTech forged and anodized aluminum crank arms utilize a hollow design that minimizes flex and keeps the weight low. HollowTech II allows the bottom bracket bearings to be spaced wider apart (outboard from the frame), enabling the use of larger bearings and an increased axle diameter; the system also allows for easier installation, adjustment, and maintenance. Lightweight anodized SG-X aluminium chainrings provide smooth and precise shifting. The chainring teeth have been developed to work in conjunction with the CN-5701 chains for increased contact to provide greater efficiency and improved power transfer.