It is a numerical expression that represents the relationship between a tire’s section height and its section width. Calculated by dividing the section height by the section width, this ratio yields a percentage. For instance, a tire marked with ‘225/50R17’ indicates a section width of 225 millimeters, a radial construction (R), a wheel diameter of 17 inches, and a height that is 50% of the 225mm width. This indicates the tires profile or how tall the tire sidewall is relative to its width.
This value is significant because it directly affects a vehicle’s handling, ride comfort, and overall appearance. A lower number signifies a shorter sidewall, typically resulting in improved cornering stability and responsiveness, though potentially at the expense of ride quality. Conversely, a higher number means a taller sidewall, often providing a smoother, more comfortable ride but with potentially reduced handling precision. Historically, this measurement has evolved to provide drivers with options that cater to specific driving preferences and vehicle requirements, influencing both performance and aesthetics.