The difference in the effort and time taken for front shifts between dura ace mechanical and di2 is truly staggering with programmed automatic motion at the touch of a switch the dura ace di2 front derailleur isquick smooth and effortless making for unmatched drivetrain efficiency 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 me