Understanding Tire Specs

Tire speed rating tells you the maximum service speed for a tire. A speed rating isn't, however, a recommendation to exceed speed limits, and doesn't indicate how well a tire handles or corners. Generally, it is recommended that a speed-rated tire be replaced with a tire having an equivalent or greater speed rating. For example, if the recommended speed rating is a V, it's suggested that you replace it with a V, W, Y, or Z. It is not recommended to fit tires with different speed ratings. If tires with different speed ratings are installed on a vehicle, they should be installed with like pairs on the same axle. The speed capability of the vehicle will become limited to that of the lowest speed rated tires. Obey all speed limits.

Tire load index is an assigned number that corresponds to the maximum weight that a tire can support when properly inflated. The higher the tire's load index number, the greater its load carrying capacity. Choosing a tire with a lower load index than the original equipment specifications means that the tire will not carry the load capacity of the original. Most passenger-car tire load indexes range from 75 to 100, but some are higher.

Tire load index is an assigned number that corresponds to the maximum weight that a tire can support when properly inflated. The higher the tire's load index number, the greater its load carrying capacity. Choosing a tire with a lower load index than the original equipment specifications means that the tire will not carry the load capacity of the original. Most passenger-car tire load indexes range from 75 to 100, but some are higher.