Having revolutionized road biking with electronic shifting, the Japanese manufacturer ups the innovation and wow-factor with its 11-speed Di2 mountain premier. But this is no simple Dura Ace Di2 repackaging.
For one, the all-new shift paddles are ergonomically superior to the mechanical versions, allowing for easy thumb shifts without the need to loosen your grip on the handlebars as is necessary in standard iterations. The shift itself is a very short throw and comes with an audible, tactile click akin to a cable-shift system. The whole setup is completely programmable, so it’s possible to customize any function, front or rear, on all four of the paddles.
What’s revolutionary is the Synchro Shift option, which enables the system to choose when to shift both front and rear derailleur based exclusively on input from the rear shifter. The system analyzes what will be the most energy-efficient gearing for the situation based on the best chain line, and then it moves either one or both derailleurs accordingly. The strong motors in the derailleurs make it possible to shift under heavy load. Given that the system can choose front and rear gearing for you, a front shifter isn’t necessary, though Shimano includes it for those who wish to maintain manual control.
There are custom-programming options ad nauseam, all done via personal computer, but the result is easier, faster, and more effective shifting than anything else out there.