TheShimano Dura-Ace RD-9070 Di2 11 Speed Rear Derailleurfeatures Digital Integrated Intellegence (Di2). Thanks to its programmed automatic motion, at the touch of a switch this rear derailleur is quick, smooth and effortless to shift, providing you with unmatched drivetrain efficiency. The removal of traditional mechanical cables in favour of electrical wires eliminates poor shifting caused by contamination, corrosion and stretching. The derailleur contains a saver (fuse) function, where the inner structure is protected from strong impacts. This rear derailleur has a 11-28T wide gear ratio capacity to cater for compact setups as well as the traditional road double. The Shimano Dura-Ace RD-9070...
Best Price: £499.99 from Leisure Lakes Bikes