>>1833067>is this an actual thing?It was a way to have multiple gears on a track bike, in a way that didn't violate UCI rules about "no derailers".
The DS has a freewheel, a lower ratio for starting from a standstill. The NDS has a longer than usual threaded bit, and a fixed cog that starts threaded all the way on, but unthreads itself until it bumps up against the lockring. The lockring is placed at a precise spot, so the fixed side (higher ratio) kicks in at some predetermined distance (say, 50 meters). The DS freewheels after that point.
