What are tire speed ratings all about?
Officially, the speed rating of a tire indicates the highest speed at which the tire can carry a specified load under specified conditions. Letters from A to Z symbolize a tire’s certified speed rating, ranging from 3 mph to above 186 mph. The speed ratings most commonly in use are: Q 100 mph V 149 mph R 106 mph W 168 mph S 112 mph Y 186 mph T 118 mph Z Zr speed capability above 149 mph. ZR_When ZR appears in the tire size designation along with a service description – such as P275/40ZR17 93W – the maximum speed rating (indicated by the “W” in “93W”) indicates the tire’s speed rating – in this case, 168 mph. In this latest effort to standardize tire designations, all ratings except unlimited Z-speed rated tires incorporate the speed symbol and load index in the tire;s service description. Example: P225/60R15 95H. the 95H is the tire’s service description indicating a maximum load carrying capacity of 1521 lbs. and a maximum speed rating of 130 mph. While all tires are speed rated to in
