Delivering a more precise feel than recirculating ball systems, rack-and-pinion steering is a common type of steering mechanism on modern automobiles. In simple terms, it consists of two gears that convert rotational movement into a linear one.
One of the gears meshes with a rack (a toothed metal bar), which in turn is directly linked to the wheels via tire rods. By rotating the gear with the steering shaft, the circular motion converts into a linear one and moving the rack from side to side, therefore turning the wheels into the desired direction.