The Shimano Dura Ace R9100 chainrings have been given a make-over and certainly look the part. The chainrings haven't just been designed to look good however. Besides the aesthetics, the tooth design has also been changed. This alters the alignment of the chain, allowing for frames to use disc brakes on shorter rear stays. The innovative 4-arm design enables you to fit all of the available gear ratios to the cranks. A double can now easily be converted to a compact, and vice versa.