The Dura-Ace ST-9000 mechanical Dual control levers represent a considerable leap forward over the benchmark 7900 levers. Shimano has been hard at work to reduce both lever throw and friction. Shifting effort has also been made more equal across the entire cassette. Less shifting force is required reducing the process of changing gears almost to the sub-conscience level with smaller, lower input hand movements for a simply wonderful shifting quality.
Changes over 7900 are significant. Lever stroke is reduced by 30% compared to the ST-7900 levers. Shifting effort for the rear derailleur is reduced up to 47% less also thanks in part to new pivots and cable clamp positioning on the RD-9000 rear derailleur. Front shifting on the 7900 could sometimes be a hair on the sticky side and Shimano addressed this by making the 9000 lighter, quicker and reducing friction by a huge 43% at the end of the shift stroke. Some of the reduction in friction is achieved with new shifter cables coated with an improved polymer that glides through the liner with less drag and holds grease very well.
Ergonomics have evolved with new levers and hood shapes. The carbon blades flairs slightly more outward and are a bit more sleek. Activating the levers from the drops or hoods is a little more friendly and there is 10mm of reach adjustment to fit all hand sizes for a tuned fit. Overall, the size of the body is a little smaller volume, similar to Di2 levers, and the hoods have a dual rubber compound to top off the improve creature comforts. All of these improvements come with a 15-gram weight reduction to boot.
For 11-speed mechanical systems only.