Home31 inch tires in metric

31 inch tire in metric

A 31 inch tire in metric depends on the wheel. The metric sizes closest to 31 in are 265/70R16 (30.61 in) on a 16 in wheel, 255/70R17 (31.06 in) on a 17 in wheel, 285/60R18 (31.46 in) on an 18 in wheel and 255/55R20 (31.04 in) on a 20 in wheel.

By David Owen. Published 3 November 2026.

Sizes are grouped by calculated diameter rounded to the nearest inch, so this page lists every catalogue size from 30.50 in up to just under 31.50 in, plus the flotation sizes whose code says 31.

in, mphmm, km/h

15 in wheels

16 in wheels

Just under the 31-inch class on a 16 in wheel: 245/75R16 at 30.47 in773.9 mm, a 30-inch tire by calculated diameter.

17 in wheels

Just under the 31-inch class on a 17 in wheel: 255/65R17 at 30.05 in763.3 mm, a 30-inch tire by calculated diameter.

18 in wheels

Just under the 31-inch class on an 18 in wheel: 255/60R18 at 30.05 in763.2 mm, a 30-inch tire by calculated diameter.

20 in wheels

Just under the 31-inch class on a 20 in wheel: 265/50R20 at 30.43 in773.0 mm, a 30-inch tire by calculated diameter.

31x10.50R15 is a flotation size: the 31 is in the code, and it's nominal.

Flotation sizes state their height and width in inches, and those numbers are nominal: makers aim at them, and real tires of the same size measure a little differently.

These are size-code figures only. Whether a size fits, clears and carries your load depends on your vehicle and the tire, so check with a tire shop.

Searched comparisons with 31-inch sizes

• 245/75R17 vs 265/70R17
• 235/75R15 vs 31x10.50R15
• 265/60R18 vs 275/65R18