Rack-and-pinion steering is one of the most common type of steering on street legal vehicles. It is a simple mechanism where the rack-and-pinion gearset is enclosed in a metal tube, with each end of the rack protruding from the tube. A rod connects to each end of the rack.
The steering ratio is the ratio of how far you turn the steering wheel to how far the wheels turn. Lighter cars have lower steering ratios than larger cars and trucks. With a lower ratio, you don’t have to turn the steering wheel as much to get the wheels to turn meaning a quicker response.