TIRE CENTER · Understanding & choosing tires
Finding and reading tire size
Photograph the complete marking
Look on the side of the tire—the sidewall. The full marking includes the size and nearby load/speed information. In the shared example, the number and letter after the size are the service description.
One tire marking, three connected lessons
Decode the size with a worked example
Width and section height
17: wheel size, not whole tire height
Your equipment’s marking may look different
| Example / prefix | What it illustrates | What to send |
|---|---|---|
| P… / no P prefix | Passenger P-metric or Euro-metric conventions | Whole marking, not a guessed prefix |
| LT215/75R15 | Light Truck metric example | Size plus service description/load information |
| 35x12.50R17LT | Flotation-format Light Truck example | All numbers, letters and application details |
| ST… | Special Trailer application marking | Trailer information plus complete marking |
| Equipment format differs | Farm, mower, ATV and other sizes may follow other conventions | Full photo; do not force it into a passenger-car format |
What to send
Share the whole marking, vehicle/equipment identity and placard/owner’s information. Installed tires are not automatically the original or correct fitment. If the format differs, send a photo rather than translating it yourself. Check front and rear separately if sizes differ.
Use the quote form’s “I don’t know my tire size” option when needed. You can still request service.
Sources and Technical Notes
Technical concepts reviewed 2026-10-10. Actual application instructions remain controlling.
- Michelin: tire markings (opens in a new tab)
- Michelin: complete 205/55R17 91V marking and ratings (opens in a new tab)
- Yokohama: sizing, application, single/dual and inflation information (opens in a new tab)
Application-specific details and scope
Nominal section dimensions are size designations, not exact measurements of every mounted tire. P-metric, Euro-metric, LT/flotation, ST and equipment conventions require their own interpretation.