265/60R18 means a 265 mm section width, a 60% aspect ratio, radial construction and a 18-inch wheel. That works out to a 159 mm sidewall and an overall diameter of about 775.2 mm.
The aspect ratio is a proportion, not a measurement: the same 45 gives a different sidewall height on a different width, and that changes both ride and handling. A lower ratio holds a corner better and transmits more of the road surface.
Body-on-frame SUVs and pickups such as the Mohave and Rexton.
What each number means
| 265 | Section width 265 mm |
|---|---|
| 60 | Aspect ratio 159 mm (60% × 265 mm) |
| R | Construction Radial |
| 18 | Wheel diameter 457.2 mm |
| Overall diameter | 775.2 mm 30.5" |
Compatible alternatives
| Size | Overall diameter | Diameter difference |
|---|---|---|
| 265/65R17 | 776.3 mm | +0.1% |
| 275/60R18 | 787.2 mm | +1.5% |
| 255/65R18 | 788.7 mm | +1.7% |
Load index and speed rating
After the size itself, a tyre wall carries something like 91V. The number is the load index — the weight one tyre can carry, 91 meaning 615 kg — and the letter is the speed rating, V meaning 240 km/h.
Never drop below the load index the manufacturer specified, even if the size matches. The original specification is printed on the label inside the driver’s door.