Over the past four years professional riders have confidence in Shimano's Di2 electronic shifting technology, in all situations of riding. Now it is time to introduce this revolutionary technology into the Shimano Ultegra, making it available to a much wider group of road racers and enthusiasts. The advantages of Di2 (Digital Integrated Intelligence) are clear for everybody who has tested it: changing gears becomes easier, effortless and faster by simply touching the shift buttons with control at the top of your fingers.
The SEIS (Shimano Electronic Intelligence System) is based on the Shimano Index System (SIS) that has proved its superior gear changing characteristics over the years. The big difference is that in this case, the shifting action is provided for by electronics instead of mechanics. It has a greater gear-ratio for use with cassettes up to 28 teeth. The electronic adjustment of the rear derailleur works also when riding the bicycle. The electronics and the servo-motors for shifting are protected from any heavy impact by a special structure design. The programmed motion allows quicker and smoother shifting with less danger of chain drop in all conditions and situations.
Note: The Ultegra Di2 products are not compatible with Dura Ace Di2.
