consists of a long metal rod with gear teeth cut into its side. When the driver turns the steering wheel, it rotates the column which, in turn, rotates a pinion gear. The pinion’s teeth mesh with the teeth on the rack, causing it to move to the left or right depending on the direction of the steering wheel.

In a power-assisted system, a hydraulic pump or electronic shaft is connected to the component to maximise the force applied by the driver to the steering wheel, making it easier to turn. Without this assistance, a lot of strength and effort would be required to turn the wheels.