ElpiAuto31X10.50R15 in metric
A 31X10.50R15 is 31.0″ (787 mm) tall and 10.50″ (267 mm) wide on a 15″ wheel. Converted directly it reads 265/75R15; the nearest standard metric size is 265/75R15.
Your tire size
e.g. 235/75R15, 33X12.50R15, or 225/45R17 91V
Metric equivalents of 31X10.50R15
No standard metric size lands exactly on 31X10.50R15. The best compromise is 265/75R15 (−1.1% height, −2 mm width); the list is ranked by height and width together, all on a 15″ wheel within ±3%.
| Size | Diameter | Height vs 31X10.50R15 | Width vs 31X10.50R15 |
|---|---|---|---|
| 265/75R15 | 30.6″ · 779 mm | −1.1% | −2 mm |
| 255/80R15 | 31.1″ · 789 mm | +0.2% | −12 mm |
| 275/75R15 | 31.2″ · 794 mm | +0.8% | +8 mm |
| 265/80R15 | 31.7″ · 805 mm | +2.2% | −2 mm |
| 285/70R15 | 30.7″ · 780 mm | −0.9% | +18 mm |
31X10.50R15 dimensions
Computed from the size code; moulded tires vary by brand by roughly 1–3%.
| Dimension | Inches | Millimetres |
|---|---|---|
| Overall diameter | 31.0″ | 787 |
| Section width | 10.50″ | 267 |
| Sidewall height | 8.00″ | 203 |
| Circumference | 97.4″ | 2474 |
| Revolutions per mile | 651 | — |
| Revolutions per km | — | 404 |
The same height on other wheels
If you are changing wheel diameter but want to keep a 31.0″ overall height, these metric sizes come closest (within 2%).
| Wheel | Size | Diameter | Difference |
|---|---|---|---|
| 16″ | 255/75R16 | 31.1″ | +0.2% |
| 17″ | 255/70R17 | 31.1″ | +0.2% |
| 18″ | 275/60R18 | 31.0″ | −0.0% |
| 20″ | 255/55R20 | 31.0″ | +0.1% |
Wheel width and neighbouring sizes
A 267 mm-wide tire mounts on 7.5–10.0″ wide wheels (the usual approved range; the middle is ideal).
One step down is 30X9.50R15: −3.2% in diameter. With a speedometer calibrated for 31X10.50R15, an indicated 60 mph would be 58.1 mph on 30X9.50R15.
One step up is 32X11.50R15: +3.2% in diameter. With a speedometer calibrated for 31X10.50R15, an indicated 60 mph would be 61.9 mph on 32X11.50R15.
Figures are geometric: overall diameter = wheel + 2 × sidewall, 25.4 mm per inch. Check the tire maker's data sheet for the exact moulded size before buying.