ElpiAuto275/55R20 in inches
A 275/55R20 is 31.9″ tall and 10.8″ wide on a 20″ wheel — about a 31.9x10.8R20 in inch/flotation notation, a 32-inch tire.
Your tire size
e.g. 235/75R15, 33X12.50R15, or 225/45R17 91V
Sizes close to 275/55R20
No standard metric size lands exactly on 275/55R20. The best compromise is 265/55R20 (−1.4% height, −10 mm width); the list is ranked by height and width together, all on a 20″ wheel within ±3%.
| Size | Diameter | Height vs 275/55R20 | Width vs 275/55R20 |
|---|---|---|---|
| 265/55R20 | 31.5″ · 799 mm | −1.4% | −10 mm |
| 285/55R20 | 32.3″ · 822 mm | +1.4% | +10 mm |
| 255/60R20 | 32.0″ · 814 mm | +0.4% | −20 mm |
| 265/60R20 | 32.5″ · 826 mm | +1.9% | −10 mm |
| 295/50R20 | 31.6″ · 803 mm | −0.9% | +20 mm |
275/55R20 dimensions
Computed from the size code; moulded tires vary by brand by roughly 1–3%.
| Dimension | Inches | Millimetres |
|---|---|---|
| Overall diameter | 31.9″ | 810 |
| Section width | 10.83″ | 275 |
| Sidewall height | 5.95″ | 151 |
| Circumference | 100.2″ | 2546 |
| Revolutions per mile | 632 | — |
| Revolutions per km | — | 393 |
The same height on other wheels
If you are changing wheel diameter but want to keep a 31.9″ overall height, these metric sizes come closest (within 2%).
| Wheel | Size | Diameter | Difference |
|---|---|---|---|
| 15″ | 285/75R15 | 31.8″ | −0.2% |
| 16″ | 255/80R16 | 32.1″ | +0.5% |
| 17″ | 255/75R17 | 32.1″ | +0.5% |
| 18″ | 295/60R18 | 31.9″ | +0.1% |
| 22″ | 255/50R22 | 32.0″ | +0.4% |
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 275/60R20: +3.4% in diameter. With a speedometer calibrated for 275/55R20, an indicated 60 mph would be 62.0 mph on 275/60R20.
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.