Product Review

Lighter and slimmer than its predecessor, the Shimano Ultegra Di2 RD-6870-SS Rear Derailleur now features an automatic protection system that moves the cage out of harm's way in the event of a crash. It'll even automatically realign itself with the cassette following an impact. Simply press and hold the shift button and the rear derailleur will go all the way up and down the cassette. When programmed at the E-TUBE platform, you can customize how many gear changes a press and hold actuates. Choose from five shifting speeds, ranging from very slow to very fast. Di2 electronic system guarantees easier, effortless, faster and more precise gear changes in demanding conditions. Shimano Electronic Intelligence System: Allows accurate and effortless shifting in challenging circumstances, like when you have cold hands or when you're completely exhausted Shifting performance is never affected by contaminated or stretched cables, since the shifting signal is transferred electronically Operating buttons work similarly to mechanical Dual Control Levers, so you don't need to learn a new system Precise, lightning-fast shifts across an 11-speed cassette, whatever the conditions, with just a button click Lighter and more compact with E-TUBE connections to simplify installation Automatic crash protection moves the cage out of harm's way Wide link design reduces shifting deflection Compatible with E-TUBE for optimum on-the-bike flexibility Short cage design