Many of today’s tires are marked, as part of the service description, with letters
to indicate their speed rating, based on laboratory tests which relate to performance
on the road. Tires may be marked with one of these speed symbols, M, N, P, Q, R,
S, T, U, H, V, W, and Y to identify the particular tire’s speed rating. Additionally,
the letter Z may appear in the size designation
When replacement of tires is required, consult the vehicle manual or tire placard
for proper size and speed rating (if required).
If the vehicle manual placard specifies speed-rated tires, the replacement tires
must have the same or higher speed rating to maintain vehicle speed capability.
Tire speed ratings do not imply that vehicles can be safely driven at the maximum
speed for which the tire is rated, particularly under adverse road and weather conditions,
or if the vehicle has unusual characteristics. Never operate a vehicle in an unsafe
or unlawful manner.
* For tires having a maximum speed capability above 149 mph (240 km/h) a “ZR” may
appear in the size designation. For tires having a maximum speed capability above
186 mph (300 km/h), a “ZR” must appear in the size designation. Consult tire manufacturer
for maximum speed when there is no Service Description. Example: P275/40R17 93W
at 168 mph (270 km/h) or P275/40ZR17 at above 149 mph (240 km/h). Consult tire manufacturer.
** A “ZR” may appear in the tire size designation.
NOTE: For “V”, “W”, or “Y”, and ties with a “ZR” rating, a vehicle load adjustment
(for speed) is required; consult tire manufacturer.