Home235/75R15 vs 31x10.50R15

235/75R15 vs 31x10.50R15

The 31x10.50R15 is 31.00 in tall: 2.12 in (7.3%) taller than the 235/75R15 at 28.88 in. At an indicated 60 mph you'd be doing 64.4 mph.The 31x10.50R15 is 787.4 mm tall: 53.9 mm (7.3%) taller than the 235/75R15 at 733.5 mm. At an indicated 100 km/h you'd be doing 107.3 km/h.

By David Owen. Published 3 November 2026.

in, mphmm, km/h

Each figure is rounded separately, so related figures can differ in the last digit.

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.

What changes

The 31x10.50R15 is a flotation size: its 31.00 in height and 10.50 in width are the nominal numbers in the size code. The 235/75R15 is metric, 235 mm wide with each sidewall 75% of that, which works out at 28.88 in tall and 9.25 in wide. On paper the 31x10.50R15 is 2.12 in taller and 1.25 in wider.

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.

Makers' own measured diameters run 28.86 to 29.09 in for the 235/75R15 and 30.5 to 31.10 in for the 31x10.50R15, against the calculated 28.88 in and 31.00 in. Real tires vary by brand and tread design; the figures in the table come from the size code alone.

Speedometer and odometer

A speedometer that read true on the 235/75R15 reads low on the 31x10.50R15: an indicated 60 mph is a true 64.4 mph.A speedometer that read true on the 235/75R15 reads low on the 31x10.50R15: an indicated 100 km/h is a true 107.3 km/h.

The odometer records about 9,320 miles for every 10,000 you drive.The odometer records about 9,320 km for every 10,000 you drive.

Ground clearance and size class

Ground clearance at the axle rises by 1.06 in: half the diameter change, unloaded.Ground clearance at the axle rises by 27.0 mm: half the diameter change, unloaded. By calculated diameter the 235/75R15 is a 29-inch tire and the 31x10.50R15 a 31-inch tire.

See every 31-inch size in metric.

Compare other sizes in the calculator