Tire Speed Rating
An alphabetical code on a tire's sidewall indicating the maximum speed the tire can safely maintain under its load limit.
A tire speed rating is an alphabetical code stamped on the tire sidewall that represents the maximum speed the tire can safely sustain over time under its recommended load capacity and inflation pressure. The ratings are determined by laboratory tests where the tire is run against a metal drum at increasing speeds to measure heat buildup and structural durability.
Speed ratings are represented by letters, typically ranging from L (75 mph / 120 km/h) for off-road tires, to S (112 mph) and T (118 mph) for standard passenger cars, and H (130 mph), V (149 mph), W (168 mph), or Y (186 mph) for high-performance sports cars. A higher speed rating indicates the tire's ability to dissipate heat and resist centrifugal forces at high speeds.
When replacing tires, it is vital to choose tires with a speed rating that matches or exceeds the vehicle manufacturer's original specifications. Mixing tires of different speed ratings on the same vehicle is not recommended, as it can adversely affect handling, cornering, and braking performance, particularly at highway speeds.