ElpiAuto275/70R18 in inches
A 275/70R18 is 33.2″ tall and 10.8″ wide on a 18″ wheel — about a 33.2x10.8R18 in inch/flotation notation, a 33-inch tire.
Your tire size
e.g. 235/75R15, 33X12.50R15, or 225/45R17 91V
Sizes close to 275/70R18
No standard metric size lands exactly on 275/70R18. The best compromise is 295/65R18 (−0.2% height, +20 mm width); the list is ranked by height and width together, all on a 18″ wheel within ±3%.
| Size | Diameter | Height vs 275/70R18 | Width vs 275/70R18 |
|---|---|---|---|
| 295/65R18 | 33.1″ · 841 mm | −0.2% | +20 mm |
| 255/75R18 | 33.1″ · 840 mm | −0.3% | −20 mm |
| 265/75R18 | 33.6″ · 855 mm | +1.5% | −10 mm |
| 265/70R18 | 32.6″ · 828 mm | −1.7% | −10 mm |
| 285/70R18 | 33.7″ · 856 mm | +1.7% | +10 mm |
275/70R18 dimensions
Computed from the size code; moulded tires vary by brand by roughly 1–3%.
| Dimension | Inches | Millimetres |
|---|---|---|
| Overall diameter | 33.2″ | 842 |
| Section width | 10.83″ | 275 |
| Sidewall height | 7.58″ | 193 |
| Circumference | 104.2″ | 2646 |
| Revolutions per mile | 608 | — |
| Revolutions per km | — | 378 |
The same height on other wheels
If you are changing wheel diameter but want to keep a 33.2″ overall height, these metric sizes come closest (within 2%).
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 down is 275/65R18: −3.3% in diameter. With a speedometer calibrated for 275/70R18, an indicated 60 mph would be 58.0 mph on 275/65R18.
One step up is 35X12.50R18: +5.6% in diameter. With a speedometer calibrated for 275/70R18, an indicated 60 mph would be 63.3 mph on 35X12.50R18.
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.