What a tire speed rating means
The speed rating is the letter at the end of the service description on the sidewall. In 225/45R17 94V, 94 is the load index and V is the speed rating. The letter gives the maximum speed at which the tire carries the load its load index allows, measured under test conditions. It is a tested limit, not a cruising speed.
V means 149 mph (240 km/h). H means 130 mph (210 km/h). W means 168 mph (270 km/h) and Y means 186 mph (300 km/h). The chart above lists every letter, from A1 at 3 mph (5 km/h) up to Y.
Tire speed rating chart
Every speed symbol with its maximum speed, in mph and km/h.
| Speed symbol | mph | km/h |
|---|---|---|
| A1 | 3 | 5 |
| A2 | 6 | 10 |
| A3 | 9 | 15 |
| A4 | 12 | 20 |
| A5 | 16 | 25 |
| A6 | 19 | 30 |
| A7 | 22 | 35 |
| A8 | 25 | 40 |
| B | 31 | 50 |
| C | 37 | 60 |
| D | 40 | 65 |
| E | 43 | 70 |
| F | 50 | 80 |
| G | 56 | 90 |
| J | 62 | 100 |
| K | 68 | 110 |
| L | 75 | 120 |
| M | 81 | 130 |
| N | 87 | 140 |
| P | 94 | 150 |
| Q | 100 | 160 |
| R | 106 | 170 |
| S | 112 | 180 |
| T | 118 | 190 |
| U | 124 | 200 |
| H | 130 | 210 |
| V | 149 | 240 |
| W | 168 | 270 |
| Y | 186 | 300 |
| Z | over 149 | over 240 |
| (W) | over 168 | over 270 |
| (Y) | over 186 | over 300 |
How to use the decoder
- A letter: type V, H or W to get its speed.
- A service description: 94V or 121/118S. The numbers are the load index and the letter is the speed rating. On a light-truck pair such as 121/118S, both numbers are load indexes and S (112 mph, 180 km/h) is the speed rating.
- The whole marking: paste 225/45ZR17 94W XL and the tool finds the speed letter and ignores the rest.
The formula
The standard defines each rating in km/h. The mph figures are the published ones, and they follow this conversion, rounded to a whole number:
mph = km/h ÷ 1.609344Worked example: V is 240 km/h, and 240 ÷ 1.609344 = 149.1, so 149 mph. Two published figures sit slightly above the exact conversion: P (150 km/h) is listed as 94 mph and Q (160 km/h) as 100 mph, where the division gives 93.2 and 99.4. The chart shows the published values.
Why H comes after U
The letters are in order of speed, not in order of the alphabet. Most of them run from A to Y, but H sits between U and V: U is 124 mph (200 km/h), H is 130 mph (210 km/h) and V is 149 mph (240 km/h). So an H tire is rated higher than a T or U tire. The letters I, O and X do not appear in the chart.
Z, (W) and (Y)
Three codes have no upper limit. Z inside the size, as in 225/45ZR17, means above 149 mph (240 km/h). (W) in brackets means above 168 mph (270 km/h), and (Y) above 186 mph (300 km/h). If a ZR size also carries a service description such as 94W, read that letter for the exact figure: W is 168 mph.
Old SR, HR and VR marks
Before 1991 the speed category was written inside the size, for example 205/60HR15. SR meant 180 km/h (112 mph), HR meant 210 km/h (130 mph), VR meant above 210 km/h and ZR above 240 km/h. Type an old size into the tool and it reads the mark for you.
What the rating assumes
The rating is measured at a set load and inflation. A tire that carries more than its rated load, runs underinflated or is damaged is outside the conditions the rating was tested in, so the letter no longer describes it.
The speed rating your vehicle needs is on the tire placard, usually on the driver's door jamb, and in the owner's manual. Rules on fitting a different rating differ from country to country, so check the rules where you drive.
Questions
What is a V speed rating?
V means the tire carries its rated load at speeds up to 149 mph (240 km/h), under test conditions. It sits above H (130 mph) and below W (168 mph).
Which is higher, H or V?
V. H is 130 mph (210 km/h) and V is 149 mph (240 km/h). On the scale, H comes after U (124 mph), not next to G.
What does ZR mean on a tire?
ZR in the size means a speed rating above 149 mph (240 km/h), with no upper limit given. If a service description follows, such as 94W, its letter gives the exact rating: W is 168 mph (270 km/h).
What does (Y) mean on a tire?
(Y) in brackets means the tire is rated above 186 mph (300 km/h). Y without brackets means up to 186 mph.
What speed rating does my car need?
Your vehicle's tire placard and owner's manual give it. This chart tells you what each letter means, not which one your vehicle needs.