Shimano Dura-Ace R9150 Di2 11-Speed Rear Derailleur SS RDR9150SS

Shimano Dura-Ace R9150 Di2 11-Speed Rear Derailleur, SS The Shimano Dura-Ace R9150 Di2 11-Speed Rear Derailleur, SS builds on Shimano Di2's reputation as one of the most advanced electronic gearing systems in the world with a lighter redesign and crisper shifting, thanks to the Synchronised Shift design. The Shimano Dura-Ace R9150 Di2 11-Speed Rear Derailleur offers crisp and instantaneous shifting with programmed automatic motion. By utilising electronic wires rather than mechanical cables, smooth shifting is assured every time you touch the lever as unlike mechanical cables, electronic wires are not affected by contaminants, corrosion or cable stretching. To protect the derailleur's inner workings from impact, Shimano has included a saver (fuse) function that reduces the threat that strong impacts pose to the internal mechanics and electronics. Compatible with an 11-30T ratio cassette or lower, this derailleur offers a wide range of gearing options from low sprint ratios to higher gearing options suitable for mountainous rides. Inside the derailleur, full carbon fibre inner and outer pulley plates increase rigidity and stiffness while also reducing weight. The pulley's themselves are constructed from tough DuPont Zytel for greater longevity and less chain noise. With Shimano's new Shadow design, this derailleur not only looks sleek but also boasts an incredibly low 204-gram reading on the scales.