U. S. Makes New Bike Shift (Sep, 1950)
U. S. Makes New Bike Shift
This new three-speed transmission gives a bicycle as many forward gears as an automobile. Made by the New Departure division of General Motors, it is designed to fit any bike having a New Departure coaster brake and can be installed in 20 minutes.
The unit consists of a sprocket and gear assembly, as shown in the cutaway above, that fits into the rear-wheel hub in place of the original sprocket. In low gear, hub and sprocket are locked, providing a direct drive that is 25 percent lower than normal, for easier hill climbing. In second, the hub turns slightly faster than the sprocket, providing a normal riding gear. In high, the hub turns still faster, providing a 33-percent “overdrive” for speed on slight downgrades.
Shifting is controlled by a cable, connected to a lever on the handle bars, that moves a sliding clutch gear back and forth inside to engage the desired set of gears. Normal braking and coasting are possible in each gear, and gears may be shifted at any time without clashing. The conversion unit, out next month, will sell for $14.50.