Shimano Ultegra Di2 Rear Derailleur
Gone is the reliance on cable tension, indexing and a spring to control rear derailleur shifts, the Ultegra 6770 Di2 Rear Derailleur uses a worm drive to eliminate the pull and pull-back associated with a derailleur spring and cable. Once properly set up, the digital derailleur shifts with ultimate precision every time.
- Programmed motion allows for quicker and smoother shifting
- Servo motor keeps gear changes identical and precise every time, as the computer control unit analyzes each shift
- Built-in crash saver function moves the derailleur inward under impact, reducing the potential for damage in the event of a crash
- Expanded chain wrap capacity accommodates a maximum 28 tooth cog for better compatibility with compact cranks
- Must be used in conjunction with the Shimano Ultegra Di2 Rear Derailleur Wire Kit, Shimano Ultegra Di2 Battery Pack, Shimano Ultegra Di2 Battery Charger and Shimano Ultegra Di2 Power Cable