To respond to the ever-growing popularity of the Di2 front derailleur, Shimano made some drastic revisions to the overall design of the FD-9000. To start, we should explain Dura-Ace 9000's shifting goal -- easier action with a shorter stroke at the lever. To achieve this, a multi-part strategy had to be developed. First, Shimano had to revise the actuation ratio -- easier said than done. By standard, Shimano has operated on a variable ratio. This means that the ratio between a unit of shifted cable and its measured movement of a derailleur is varied throughout the gear range. As Shimano sees it, every gear jump is different, and requires a variance in actuation. However, to minimize the stroke effort, the variable ratio had to be lessened. This required a replacement of the leverage points on the front derailleur's body. You'll notice that FD-9000 now has a heightened profile with the leverage point at the top of the body. The enlarged pull arm creates more leverage, and this strengthens the pull, eases the actuation, and thus lessens the shift stroke.
All in all, Shimano claims that the new derailleur system creates a 43% reduction in shifting effort over 7900 at the lever. And to round things off in the efficiency department, the FD-9000 is pulled by Shimano's proprietary, polymer-coated shift cable. Shimano's new cable nearly eliminates mechanical drag, and further enhances shift accuracy. Altogether, the minimization of stroke and required effort creates a shifting experience on-par with the accuracy found in Di2 systems. 9000 guarantees predictability and ease across the shifting range, and to accommodate for FC-9000's 55 tooth chainring capacity, Shimano reintroduced its micro-trim system. In this iteration, it works opposite to prior generations, in that the trim moves outward for wide-open, cross-chain compatibility.
The Shimano Dura-Ace FD-9000 11-Speed Front Derailleur is available in one color and as either a braze-on or clamp. The clamp is offered in both a 31.8mm/28.6mm or 34.9mm clamp diameter. Please note that the FD-9000 is intended for use with the Dura-Ace 9000 component group.