Shimano’s second tier electronic group retails for less than Dura Ace mechanical, albeit only $20 less, but it is a whopping $1500 less than Dura Ace Di2. What do you give up to save all that money? Nothing important. There are three things electronic drive trains do better than any mechanical system and Ultegra Di2 does each of them, and incredibly well. First is the ability to auto trim the front derailleur ensuring chain rub is nonexistent, second is the ability to shift the front derailleur under enormous effort, even out of the saddle, and thirdly it is their penchant for staying perfectly adjusted for thousands of miles. Ultegra Di2 doesn’t just do these things, it does them as well as Dura Ace Di2.

Where does the group fall short? Other than materials, the main difference is in the servo-motors. Shimano sourced bigger and less efficient motors to drive Ultegra Di2 derailleurs. This has resulted in a bulkier look, 260 extra grams and shorter battery life. They also feel a hair slower to shift than Di2, but unless you are a dedicated Dura Ace Di2 rider, you won’t notice. If a rider was concerned about any of those differences they shouldn’t be riding electronic anyway. If you are that worried about weight, mechanical is lighter, if battery life or your derailleur’s size worries you, again, ride mechanical. While less efficient than Dura Ace Di2 you can still get 1500 shifts per charge out of Ultegra Di2’s battery, that’s a lot of miles.

What is perhaps more surprising is an argument can be made that Ultegra Di2 is better and in fact, many of its features will eventually turn up in an updated Dura Ace Di2. The wires are truly plug and play, not to mention waterproof out of the box. Slimmer, more flexible and a one-pin connector, makes for a set up that is quicker, easier, lower profile, and requires smaller holes for internal routing than Dura Ace Di2. The trim function has 30 different steps to dial in flawless shifting, while Dura Ace Di2 has 24. You can even buy an external diagnostic device that you simply plug into one of the levers and get a snap shot of each component. The device even lets you customize which button does what. Want to shift the big ring with your right lever?

Ultegra Di2 can be had on bikes costing less than $5000, that new entry level threshold. This puts it in an exponentially larger market. Chances are it will out sell Dura Ace Di2 10 to 1 in 2012. The absolute perfection of its shifts also mean that the less cycling obsessed, and less experienced, rider has even more to gain from an electronic drive train. Never miss shift again. Ultegra Di2 will be the tipping point that creates an electronic peloton. In short order mechanical drive trains will be as out dated as the down tube shifter, and it will be due to Ultegra Di2.

Ultegra Di2 6770 Weight: 2482 grams Price: $2308