Speed ratings signify the safe top speed of a tire under perfect conditions.

The speed rating of a tire is generally listed after the tire size and "load rating" Example: 225/45R17 92V, the preceding size is an "V" speed rated tire. Sometimes, a "Z" speed rating is listed before the "R" Example: 225/45ZR17. A "W" or "Y" rated tire can be substituted for a "Z" speed rated tire.

NOTE: The speed rating of a tire has nothing to do with the actual size of the tire. So a 195/65R15 89H tire can be substituted for a 195/65R15 89S tire. However, to maintain the performance characteristics of the vehicle it is recommended that a higher speed rating be substituted.

NOTE 2: Light truck "LT" tires are not required to have speed ratings.