The 2017 Shimano Dura Ace Di2 9150 Groupset is a top-of-the-line electronic-shift road group. The latest instance of this high-performance championship group has some refinements and some larger changes; among the latter category are the introduction of a power meter and the incorporation of the off-road Shadow rear derailleur mechanism into the RD-R9150 mech. Among the more modest changes, a new look: the lines are sharper across the board, from the new, wider brake calipers, capable of surrounding a 28mm tire, to the front derailleur. The combination levers have also been refreshed; the lever itself is a bit smoother, and the hoods are textured.
A very good road group.