If the Dura-Ace 9000 dual control levers and brakes are perhaps the most improved components, the FC-9000 crankset is visually the most striking thanks to its 4-arm asymmetric spider and polished silver/gloss black finish. The idea behind the four-arm spider was to position strength exactly where it was needed at the power portion of the pedal stroke so you get the same incredible stiffness of the FC-7900 crank at a 52 gram lower weight.
One of the most exciting features of the 9000 crank is a multitude of chainring offerings that all bolt to the 110mm bolt circle diameter, asymmetric 4-arm crank. This is possible because the incredibly light and stiff Hollowglide outer chainring that matches the stiffness of 130mm BCD chainrings. Chainring options include 50-34t, 52-36t, 52-38t, 53-39t, 54-42t and 55-42t. Interestingly enough, chainring spacing is the same as 7900 but the tooth profiles are optimized for 11-speed.
Shimano retains the tried and true Hollowtech II system with its 24mm hardened steel spindle. The Hollowtech II design offers more than enough stiffness and makes installing and removing the crank a snap for easy cleaning and service.