How to use it
- Find the service description on the sidewall, right after the size: two or three digits and a letter, like 91V or 112T.
- Type it, or pick the letter in the chart.
- Read the maximum speed in mph and km/h, and the load the number stands for.
Speed rating chart
| Rating | mph | km/h | Often found on |
|---|---|---|---|
| L | 75 | 120 | Off-road and some light truck tires |
| M | 81 | 130 | Temporary spares |
| N | 87 | 140 | Temporary spares |
| P | 93 | 150 | Light truck tires |
| Q | 99 | 160 | Winter and light truck tires |
| R | 106 | 170 | Light truck tires |
| S | 112 | 180 | Family cars and vans |
| T | 118 | 190 | Family cars and minivans |
| U | 124 | 200 | Rare in the US |
| H | 130 | 210 | Sedans, coupes and crossovers |
| V | 149 | 240 | Sport sedans and coupes |
| W | 168 | 270 | High-performance cars |
| Y | 186 | 300 | High-performance cars |
The letters run in alphabetical order except H, which sits between U and V. A rating is a laboratory test speed, not a recommended driving speed: underinflation, overloading, wear, damage and heat all reduce what a tire can take.
Decoding 91V
| Part | Meaning |
|---|---|
| 91 | Load index: up to 1,356 lb (615 kg) per tire |
| V | Speed rating: up to 149 mph (240 km/h) |
ZR and (Y)
ZR in the size, as in 225/40ZR18, marks a tire made for speeds above 149 mph (240 km/h). Modern ZR tires also carry a normal service description such as 92W or 92Y. A Y in parentheses, as in (92Y), means the tire is rated above 186 mph (300 km/h); the tire maker states the exact limit.
Can you use a lower speed rating?
Fit tires with a speed rating equal to or higher than the one on your vehicle's tire placard or in the owner's manual. A lower rating usually means a tire built for less heat and load at speed, and it can change how the car handles. Avoid mixing ratings; if you must, keep matching pairs on each axle and treat the lowest rating as the limit for the whole vehicle.
Winter tires are the usual exception: some vehicle makers allow winter tires with a lower speed rating than the original, sometimes with a reminder sticker on the dashboard. Check the owner's manual before counting on it.
Questions
Is a V speed rating better than H?
V is certified for a higher speed: 149 mph (240 km/h) against 130 mph (210 km/h). It often has a stiffer construction that can ride firmer. Going from H to V is generally accepted; going from V to H is not recommended.
What speed rating do I need?
At least the one on the tire placard in the driver's door jamb or in the owner's manual. The vehicle maker chose it for the vehicle's top speed and weight.
Where is the speed rating on a tire?
Right after the size, at the end of the service description. In 225/65R17 102H, the speed rating is H.
What does Z mean on a tire?
ZR in the size marks a tire for speeds above 149 mph (240 km/h). Today it appears together with a W or Y rating, which gives the exact limit.