A tire speed rating reflects the maximum speed at which a tire can safely operate over an extended period. Simply put, it's the highest speed a tire can reach before it ceases to perform as intended. A higher speed rating equates to superior control and handling at higher velocities.
Tire speed ratings were introduced to standardize and control tire performance at safe speeds. Tires receive a speed rating assigned from A to Z, denoting speeds from 5km/h (3mph) up to and exceeding 300 km/h (186 mph).
This rating system outlines a tire's top certified speed, but it doesn't reflect the tire's overall performance capacity.
Tire speed ratings were initially developed in Europe to standardize and ensure the safe performance of tires at consistent speeds. The top speed rating originally was the "Unlimited V" category, designated for speeds exceeding 210 km/h (130 mph).
As tire manufacturers innovated and produced more efficient tires, there arose a need to standardize performance at specific speeds for safety reasons. This led to the creation of the "Limited V" category for speeds up to 250 km/h (149 mph) and subsequently, the "Z" speed rating for the highest speeds. For the maximum speed of Unlimited Z tires, always refer to the manufacturer.
Your tire speed rating can be found in various locations such as the owner’s manual, the driver’s side doorjamb, the glove box door, and the fuel tank hatch. With recent standardization, all ratings apart from "Unlimited ZR" incorporate the speed symbol and load index as part of the tire's service description on the sidewall. When looking at your tire sidewall, the speed rating is the final element in the tire’s size code sequence. For example, in the tire size code 2015/60R15 91V, the speed rating is V, implying that V-rated tires can safely reach speeds up to 149 MPH.
Tires capable of reaching speeds over 149 MPH may have a "ZR" label in their size designation. For those with a top speed capability exceeding 186 MPH, the inclusion of "ZR" in the designation is a requirement. Examples of tire sizes with a "ZR" speed rating are provided below.
For tires designed for speeds over 240 km/h (149 mph), the size designation may include a "ZR". Similarly, tires capable of speeds over 300 km/h (186 mph) necessitate the "ZR" label in their size designation. For maximum speeds when no service description is available, please refer to the tire manufacturer.
| Speed Symbol | Speed (km/h) | Speed (mph) |
|---|---|---|
| A1 | 5 | 3 |
| A2 | 10 | 6 |
| A3 | 15 | 9 |
| A4 | 20 | 12 |
| A5 | 25 | 16 |
| A6 | 30 | 19 |
| A8 | 40 | 25 |
| B | 50 | 31 |
| C | 60 | 37 |
| D | 65 | 40 |
| E | 70 | 43 |
| F | 80 | 50 |
| G | 90 | 56 |
| J | 100 | 62 |
| K | 110 | 68 |
| L | 120 | 75 |
| M | 130 | 81 |
| N | 140 | 87 |
| P | 150 | 94 |
| Q | 160 | 100 |
| R | 170 | 106 |
| S | 180 | 112 |
| T | 190 | 118 |
| U | 200 | 124 |
| H | 210 | 130 |
| V | 240 | 149 |
| W | 270 | 168 |
| Y | 300 | 186 |