Shimano Dura Ace Di2 9070

The 2016 Shimano Dura Ace Di2 9070 is a top-of-the-line electronic-shift road groupset. The latest edition of Shimano's flagship road group incorporates an 11-speed cassette and a plethora of incremental improvements, from twin bearings in the dual-pivot brake calipers to new ergonomics in the lever hoods.
The electronics have been extensively revamped. A single wire connection not only cleans up routing, it offers easy addition of satellite shifters. The front derailleur automatically trims itself on a rear shift, eliminating chain rub. Automatic crash protection moves the rear derailleur out of harm's way.
The Hollowtech II crankset is spectacularly efficient, and an ace choice for nearly any rider: six options in gearing, from a 55/42 to a compact 50/34, and arm lengths from 165 to 180mm. The rings mesh seamlessly with the HG chain, its PTFE coating minimizing friction and providing very smooth shifts.
The hubs have changed very little. Already light, fast-rolling, durable, and reliable, this version is the recipient of an updated seal. Compatible with either 10 or 11-speed cassette. The cassette is offered in five ranges, from a tight 11-23 up to 12-28.
An excellent road group.