The cold-forged aluminium alloy Dura-Ace crankset comes with a new hollowed out chainring. The chainring bolts slot through the inner chainring and screw directly through the spider and into the outer chainring. Shimano claim this design is 20 percent stiffer than any of their previous cranks.
The tooth proﬁles on the chainrings have been redesigned to reduce wear and improve efﬁciency, not only when shifting, but also when transferring power from the chainring to the chain.
The bottom bracket has stainless steel bearing units as usual, but with new seals with less drag than previous versions. The chainset weighs in at 739g, including bearings.
On the road this is one of the stiffest feeling cranksets we’ve ever ridden. Only Cannondale’s Hollowgram SI system and the THM Clavicula cranks are comparable in terms of how stiff they feel when pedalling.