Gearbox bicycle

A gearbox bicycle is a bicycle that uses a gearbox[1][2] to convert torque and rotational speed from the power source, usually the rider's legs, to what is desired at the drive wheel.

[3] Cited advantages include improved shifting performance,[4] protecting the gearing from damage and exposure to dirt and moisture,[5] as with hub gears, plus locating the additional mass between the two wheels and on the frame where it may be suspended,[6] unlike with hub gears.

[7] Patents for built-in systems to change gear ratios appeared as early as 1890.

[10] Several attempts to develop gearbox bicycles during the 2000s for downhill racing, such as the Honda RN-01 G-cross, incorporated complete derailleur gear drive trains in an enclosure.

[11][12] Around the same time Schlumpf Innovations and Hammerschmidt offered cranksets with two different gear ratios and just one chainring.