ElpiAuto275/65R18 in inches
A 275/65R18 is 32.1″ tall and 10.8″ wide on a 18″ wheel — about a 32.1x10.8R18 in inch/flotation notation, a 32-inch tire.
Your tire size
e.g. 235/75R15, 33X12.50R15, or 225/45R17 91V
Sizes close to 275/65R18
No standard metric size lands exactly on 275/65R18. The best compromise is 255/70R18 (−0.1% height, −20 mm width); the list is ranked by height and width together, all on a 18″ wheel within ±3%.
| Size | Diameter | Height vs 275/65R18 | Width vs 275/65R18 |
|---|---|---|---|
| 255/70R18 | 32.1″ · 814 mm | −0.1% | −20 mm |
| 295/60R18 | 31.9″ · 811 mm | −0.4% | +20 mm |
| 265/65R18 | 31.6″ · 802 mm | −1.6% | −10 mm |
| 285/65R18 | 32.6″ · 828 mm | +1.6% | +10 mm |
| 265/70R18 | 32.6″ · 828 mm | +1.7% | −10 mm |
275/65R18 dimensions
Computed from the size code; moulded tires vary by brand by roughly 1–3%.
| Dimension | Inches | Millimetres |
|---|---|---|
| Overall diameter | 32.1″ | 815 |
| Section width | 10.83″ | 275 |
| Sidewall height | 7.04″ | 179 |
| Circumference | 100.8″ | 2559 |
| Revolutions per mile | 629 | — |
| Revolutions per km | — | 391 |
The same height on other wheels
If you are changing wheel diameter but want to keep a 32.1″ overall height, these metric sizes come closest (within 2%).
| Wheel | Size | Diameter | Difference |
|---|---|---|---|
| 15″ | 255/85R15 | 32.1″ | −0.0% |
| 16″ | 255/80R16 | 32.1″ | −0.0% |
| 17″ | 255/75R17 | 32.1″ | −0.0% |
| 20″ | 255/60R20 | 32.0″ | −0.1% |
| 22″ | 255/50R22 | 32.0″ | −0.1% |
Wheel width and neighbouring sizes
A 275 mm-wide tire mounts on 8.0–10.5″ wide wheels (the usual approved range; the middle is ideal).
One step up is 33X12.50R18: +2.9% in diameter. With a speedometer calibrated for 275/65R18, an indicated 60 mph would be 61.7 mph on 33X12.50R18.
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.