|Symbol||Max Speed (mph & km/h)||Symbol||Max Speed (mph & km/h)|
|Q||99 mph||R||106 mph|
|U||124 mph||H||130 mph|
|V||149 mph||W||168 mph|
|Symbol||Max Speed (mph & km/h)|
Z-speed rated tires originally reflected the hightest speed rating. When new cars were developed that could exceed this speed, the automotive industry added the W and Y rating. While a Z-rating still often appears, such as : 215/50ZR16 91W ... the Z in the size signifies a maximum speed capability in excess of 149 mph; the W in the service description indicates the tire’s 168 mph maximum speed. When the Y-rating in a service description is enclosed in parentheses such as 285/35ZR19 (99Y), the top speed of the tire has been tested in excess of 186 mph.