How to read a tire size
The code on a tire's sidewall, like P225/60R17 98H, tells you its size, how much weight it carries and how fast it can safely go.
P225/60R1798H
- P: tire type. P is a passenger tire, LT a light truck tire, T a temporary spare. No letter means a Euro-metric passenger tire.
- 225: tread width in millimeters, sidewall to sidewall.
- 60: aspect ratio. The sidewall is 60% as tall as the tire is wide (135 mm here).
- R: radial construction.
- 17: wheel diameter in inches.
- 98: load index. 98 means up to 750 kg (1,653 lb) per tire.
- H: speed rating. H means up to 130 mph.
Speed ratings
| Rating | Max speed | Typical use |
|---|---|---|
| M | 81 mph | Temporary spares |
| Q | 99 mph | Winter tires |
| S | 112 mph | Family cars, minivans |
| T | 118 mph | Family cars, minivans |
| H | 130 mph | Sedans, crossovers |
| V | 149 mph | Sport sedans |
| W | 168 mph | Performance cars |
| Y | 186 mph | High-performance cars |
Other markings you'll see
- DOT code: ends in four digits giving the week and year it was made. 2524 means week 25 of 2024.
- XL or Extra Load: a reinforced tire rated to carry more at a higher pressure.
- M+S: mud and snow. The three-peak mountain snowflake symbol means it passed a severe-snow test.
- Max pressure: the most the tire can hold, not the pressure to run. Use the figure on your door-jamb label.
Questions
What does P mean on a tire size?
P stands for P-metric, a passenger car tire built to US standards. A size with no letter in front is Euro-metric. LT means light truck and T means a temporary spare.
What does R mean on a tire?
R means radial construction, which almost every modern car tire uses. D means diagonal (bias-ply) and turns up mostly on temporary spares.
Is a higher load index better?
A higher load index means the tire can carry more weight. Replacements should match or exceed the original load index, never go below it.
Where is the tire size on my car?
On the tire sidewall, and on the label inside the driver’s door jamb, which also gives the recommended pressures. Your owner’s manual lists every factory size for the model year.