Spy shots of new Dura Ace 9000-series are wafting over from Japan. This is the new crank, a departure from the 130mm bcd 5-arm that has been traditional for Shimano’s top racing crank for decades. The four arm bcd looks fairly small, so I’d guess that the same forging will probably be used for both standard racing combinations (e.g. 53/39) and compact gearing (e.g. 50/34). It is interesting that the spider arms are not evenly spaced around the face of the crank; they seem to have narrower angles between the spider arms in the direction perpendicular to the crank arms. Besides the marketing benefits of system integration, this arrangement concentrates support for the chainrings where they will see the most stress (i.e. when the crank arms pass thru 3 o’clock). Shimano has been an industry leader in chainring design for 20 years now, and this latest version of Dura Ace uses the strength and rigidity of the hollow chainring (first introduced with DA 7900) to allow the spider bcd to be paired down. Aesthetically, I am undecided on the new cranks style, but I think it may be growing on me.
Brakes are another facet that has been a standout for the last 5 generations of Dura Ace. Though I’m sure they stop awesome, but these brakes are hideous. I’m not quite sure how the pivots are laid out from just seeing the front of the caliper, but I’m very curious.