Every tire is designed to withstand a specific level of speed over an extended period of time – think in terms of highway driving for example. The longer you drive at a certain speed, the more heat a tire will generate from the friction of that tire churning against the road surface and the side wall flexing.
A tire’s speed rating indicates the ability of that tire to handle a certain level of prolonged speed – and the heat it produces – without suffering deterioration in performance.
All tires in the in the U.S. are designed to maintain legal U.S. speed limits. A tire’s speed rating must match the maximum driving speed of the vehicle it’s mounted on. However, simply installing a tire rated for a designated speed does not mean the vehicle it’s mounted on can be driven safely at the tire’s highest performance level.
Below is a list of ratings coordinated with the speeds they represent. Note: These are not recommended speeds.
|Rating||Maximum Speed||Typical Application|
|L||75 mph | 120 km/h||Off-Road & Light Truck Tires|
|M||81 mph | 130 km/h|
|N||87 mph | 140 km/h||Temporary Spare Tires|
|P||93 mpg | 150 km/h|
|Q||99 mph | 160 km/h||Studless & Studdable Winter Tires|
|R||106 mph | 170 km/h||H.D. Light Truck Tires|
|S||112 mph | 180 km/h||Family Sedans & Vans|
|T||118 mph | 190 km/h||Family Sedans & Vans|
|U||124 mph | 200 km/h|
|H||130 mph | 210 km/h||Sports Sedans & Coupes|
|V||149 mph | 240 km/h||Sports Sedans, Coupes & Sports Cars|
|Z||> 149 mph, 240 km/h|
|W (Z)||168 mph | 270 km/h||Exotic Sports Cars|
|Y (Z)||186 mph | 300 km/h||Exotic Sports Cars|
The load index is a numerical identifier assigned to each tire based on the ability of that tire’s size to withstand a certain load level of speed without deterioration in performance. The higher the load index value, the greater the load the tire can safely carry at the correct inflation.
Note: Pep Boys will only install tires that meet or exceed the original equipment manufacturers specifications for specific rating and load index.