Variable – ratio steering is a system which uses different ratios on the ball, in a rack and pinion steering system. At the center of the rack, the spaces between the teeth are smaller and the spaces become larger as the pinion moves down the rack. In the centre of the rack you'll have a superior ratio and the ratio becomes inferior as you turn the steering wheel towards lock. This makes the steering less responsive when the steering wheel is close to its center position, other than it makes it harder for the driver to over steer at high speeds. As one turns the steering wheel towards lock, the wheels begin to respond more to your steering input. This ratio quickens near the extremes of steering lock so as to decrease the amount of steering effort necessary during low – speeds maneuvering such as parallel parking.
The steering ratio, is the sum of degrees you turn the steering wheel, for the wheels to turn an amount of degrees. In motorcycles and bicycles, the steering ratio is always 1:1, since the steering wheel will always follow the wheel. The ratio x: y implies that you have turn the steering wheel x degree(s) in order for wheel(s) to turn y degree(s). In the majority passenger cars, the ratio is between 12:1 or 20:1 (For Example, If one complete turn of the steering wheel, 360 degrees, causes the wheels to turn 24 degrees, the ratio is then 360:24 = 15:1 (360/24=15)).
A higher steering ratio means that more you have to turn the steering wheel so as to get the wheels turning though it will be easier to turn the steering wheel. A lower steering ratio is the vice – versa of higher steering ratio.