How Do I Check A Tire's Speed Rating?

It's a very common question -- what is the speed rating on my tires? And of course, what does that mean? The practice of branding a speed rating on tires began in Germany, where some highways don't have speed limits, as a way to ensure the speed capability of the tires were matched with the top speed capability of the vehicle they’re mounted on.

Using the P195/60R15 87S tire in the image below as our example, the speed rating is denoted by the "S" at the very end.

\n\nWhen Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of vehicles that have extremely high top-speed capabilities.

While a Z-speed rating still often appears in the tire size designation of these tires, such as 225/50ZR16 91W, the Z in the size signifies a maximum speed capability in excess of 149 mph, 240 km/h; the W in the service description indicates the tire's 168 mph, 270 km/h maximum speed.

When the Y-speed rating indicated 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, 300 km/h indicated by the service description as shown below: