How to read your tire size
Short answer: in a size like 225/65R17 102H, 225 is the tire's width in millimetres, 65 is the sidewall height as a percentage of that width, R means radial construction, 17 is the wheel (rim) diameter in inches, 102 is the load index and H is the speed rating.
Where to find your size
Look on the sidewall of your current tire, the placard inside the driver's door jamb, or your owner's manual. The door placard is the size your vehicle maker recommends.
Each part of 225/65R17 102H
- 225
- Section width in millimetres, sidewall to sidewall.
- 65
- Aspect ratio: the sidewall is 65% as tall as the tire is wide. Lower numbers mean a shorter, sportier sidewall.
- R
- Radial construction, used on almost every passenger tire today.
- 17
- Fits a 17-inch wheel. Tire and rim diameter must match exactly.
- 102
- Load index: the maximum weight per tire (102 = 850 kg). Never go below your vehicle's original load index.
- H
- Speed rating: the maximum sustained speed the tire is built for (H = 210 km/h).
Letters before and after the size
- P (P225/65R17): passenger tire.
- LT (LT245/75R16): light-truck tire, built for heavier loads and towing.
- C (235/65R16C): commercial or van tire.
- XL: extra load, rated for more weight at higher pressure.
- 33X12.50R20LT: off-road (flotation) sizing in inches: 33" tall, 12.50" wide, for a 20" wheel.
Speed ratings
| Letter | Max km/h |
|---|---|
| Q | 160 |
| R | 170 |
| S | 180 |
| T | 190 |
| H | 210 |
| V | 240 |
| W | 270 |
| Y | 300 |
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