Fit Shimano’s Positron and Front Freewheeling systems to your bike and it can do it all! Shift without guess work, shift while coasting, shift positively into each gear, shift before mounting and even shift while back pedaling. The only thing that it can’t do is lower ‘Big G’ - the universal gravitational constant - so unfortunately your bike will weigh what we earthlings call ‘a ton’.
Browse associated derailleurs.
Shimano 400 FF (DC400F) 1977?