A Transmission or Gearbox provides speed and torque conversions from a rotating power source to another device using gear ratios. The most common use is in motor vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels.
Such engines need to operate at a relatively high rotational speed, which is inappropriate for starting, stopping, and slower travel. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process.
Transmissions are also used on pedal bicycles, fixed machines, and anywhere else rotational speed and torque needs to be adapted. Helical and planetary reduction gear boxes for horizontal & vertical application with different gear ratios are common in use.

A Transmission or Gearbox provides speed and torque conversions from a rotating power source to another device using gear ratios. The most common use is in motor vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels.
Such engines need to operate at a relatively high rotational speed, which is inappropriate for starting, stopping, and slower travel. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process.
Transmissions are also used on pedal bicycles, fixed machines, and anywhere else rotational speed and torque needs to be adapted. Helical and planetary reduction gear boxes for horizontal & vertical application with different gear ratios are common in use.