Available in autumn/fall 2008, Shimano’s new mechanical Dura-Ace groupset loses over 135g while maintaining its durability and with improved performance and ergonomics.
The FC-7900 Dura-Ace Crankset utilises the Hollowtech II hollow forged crank as a benchmark for strength to weight performance characteristics. Combined with a hollow outer chainring the crankset is 20% stiffer for optimal power transfer while still saving 15g. Other changes include redesigned chainring teeth for better contact and power transfer. Improved bottom bracket seals further reduce contamination and friction.
The new ST-7900 Dual Control levers offer a refined ergonomic shape while reducing weight by over 40g. With a Shimano first, the new STI levers offer unidirectional carbon fibre lever blades which reduce weight and offer shift cables hidden under the handlebar tape for a more sleek design. Using a revised internal mechanism along with PTFE lined casing, the shifting is still as light as ever.
Shifting stroke for the rear derailleur has been reduced by 20% for quicker shifts and a built in reach adjuster allows for fine tuning the fit for riders with smaller hands. The shifters continue to have integrated controls for the all new FlightDeck computer (SC-7900), which has been updated to include heart rate, altitude, grade, cadence, gear position, and directly downloadable data via a wireless connection. The new SC-7900 is completely wireless.
The new CN-7900 Dura-Ace chain has redesigned plates that improve the contact interface with the cogs and reduce the chance for chain suck on the chainrings. Other improvements to the links provide greater durability, with less noise and smoother function. The chain uses hollow pins and weight drops by over 18g even with the addition of a quick connection/removal link. A departure from the traditional Hyperglide connection pin, the SM-CN79 quicklink provides a reusable connection and removal point for the chain. The quicklink can be used on any Shimano 10-speed chain and the new chain can also be joined by a traditional Hyperglide 10-speed connection pin if necessary.
With a new carbon fibre rear pulley cage, the RD-7900 Dura-Ace rear derailleur loses another 16g while maintaining durability and improving performance. The new design is compatible with wider range cogsets and can accommodate a maximum 28 tooth cog. The available wider range creates even better compatibility with compact cranksets.
The new FD-7900 Dura-Ace front derailleur cage eliminates the need to manually trim the front shifting. Additionally, the redesigned, more efficient wide linkage and optimized spring tension combine for reduced shifting effort.
Increased linear response, improved braking power, and reduced weight all make their way into the latest version of the Dura-Ace brakes. A new brake pad compound doubles wet condition performance, while also improving dry power by a claimed 20%. Enhanced linear response comes from a redesigned caliper arch, while a lower profile cable stop creates better lines for the cables and reduces cable friction.
Both the FH-7900 / HB-7900 Dura-Ace Freehub and Front Hub have evolved to improve rigidity for efficient power transfer and quick handling. The bearings have been updated with a new tool-free bearing adjuster for quick bearing adjustments. The freehub continues with the durable titanium shell and quick engagement internals.
Shifting has been further improved by creating a more rigid (and lighter) aluminium carrier unit along with a re-engineered teeth profile. Cassette design is lighter as Shimano has developed a super lightweight and rigid aluminum cassette sprocket carrier. The largest four cogs are titanium and weight is reduced by 10 grams. Available combinations will be: 11-21T, 11-23T, 11-25T, 11-27T, 11-28T, 12-23T, 12-25T, 12-27T.
