Shimano ultegra di2 6870 11 speed front mechthe di2 front derailleurs operation is pioneering smooth shifting is guaranteed thanks to a microchip communication link with the gear levers whats more shifting the rear derailleur automatically trims the front derailleur the biggest difference you will notice is just how much quicker and effortlessly smoother shifting on the front chainrings is even under load the difference in the effort and time to actuate the shift between mechanical and di2