Gears are round, toothed devices which facilitate the production of torque from engine speed. They are either mounted to gearbox drive shafts or part of the same. The commonly used gears have a hole at the centre, which is called a bore and that secures the gear shaft. Upon rotation of the gear shaft, the gear rotates as well.

Acting as the axle of the gear, the gear shaft allows its rotation and subsequent turning and engagement. This is called gear reduction or transfer of horsepower and it ...