Passenger Tire Service Description

Most tires today have a service description branded on the side wall after the tire size. This service description consists of two parts: The load index and the speed symbol. The load index is a number usually between 75 and 115, which identifies the tire's load capacity at maximum inflation. Higher numbers mean greater load capacity. The speed symbol is a letter usually between P and Z, which defines the speed capability of the tire. In the past, this letter might have been part of the tire size; this continues to be the case with some V and Z rated tires. The higher the letter, the greater the speed capability. Tire companies have charts which define equivalent loads and speed for all load indexes and speed symbols that make up the tire service description.

Important: When replacing tires, never install a tire that is a smaller size or lesser speed rating than that used as original equipment. The speed rating only applies at the tire's full pressure. An under-inflated tire will not meet its speed rating capability.

The chart below shows the common speed rating on tires used.

Speed Symbol Maximum Speed
S 160 km/h (112 mph)
T 190 km/h (118 mph)
U 200 km/h (124 mph)
H 210 km/h (130 mph)
V 240 km/h (149 mph)
Z Over 240 km/h (Over 149 mph)