When "ZR" appears in the size designation with the service description, the maximum speed is as indicated by the service description.
P275/40ZR17 93Y Maximum Speed
93W 270 km/h (168 mph)
300 km/h (186 mph)
For tires having a maximum speed capability above 240 km/h (149 mph), a "ZR" may appear in the size designation.
For tires having a maximum speed capability about 300 km/h (186 mph), a "ZR" must appear in the size designation.
Consult the tire manufacturer for maximum speed when there is no service description.