How Ring & Pinion Gears Work

Ring and pinion gears are the automotive hardware that rotates the wheels of a car backwards and forwards. They are commonly used in the the drive systems of tractor-trailers and larger pickup trucks meant to carry heavy loads. A ring and pinion gear set is made up of a ring with grooves that are connected to the axles of the rear wheels and of a grooved pinion that is connected to the front wheel. The mechanics of ring and pinion gears allow the rear-wheel drive feature to work correctly.


Ring and pinion gears work in conjunction with the drive shaft to create torque for the drive wheels. This happens quickly whenever the driver presses the car's accelerator. The pinion and drive shaft are attached and therefore must spin together to generate enough torque that in turn creates the power that moves the wheels forward.

Ratio of Grooves

The performance of ring and pinion gears depends on the ratio of grooves in both the ring and pinion. The bigger this ratio, the more force is created. Rings and pinions are also designed with teeth that help the drive shaft generate enough needed torque. The ratio of teeth and groove size needs to be equal for the ring compared to the pinion, or else they will eventually wear out.