Home275/55R20 vs 285/55R20

275/55R20 vs 285/55R20

The 285/55R20 is 32.34 in tall: 0.43 in (1.4%) taller than the 275/55R20 at 31.91 in. At an indicated 60 mph you'd be doing 60.8 mph.The 285/55R20 is 821.5 mm tall: 11.0 mm (1.4%) taller than the 275/55R20 at 810.5 mm. At an indicated 100 km/h you'd be doing 101.4 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

Only the section width changes, from 10.83 in to 11.22 in. The aspect ratio is a percentage of the width, so each sidewall grows with it, by 0.22 in, and the 285/55R20 ends up 0.43 in taller overall.

Makers' own measured diameters run 31.89 to 32.13 in for the 275/55R20 and 32.36 to 32.60 in for the 285/55R20, against the calculated 31.91 in and 32.34 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 275/55R20 reads low on the 285/55R20: an indicated 60 mph is a true 60.8 mph.A speedometer that read true on the 275/55R20 reads low on the 285/55R20: an indicated 100 km/h is a true 101.4 km/h.

The odometer records about 9,870 miles for every 10,000 you drive.The odometer records about 9,870 km for every 10,000 you drive.

Ground clearance and size class

Ground clearance at the axle rises by 0.22 in: half the diameter change, unloaded.Ground clearance at the axle rises by 5.5 mm: half the diameter change, unloaded. By calculated diameter both are 32-inch tires.

See every 32-inch size in metric.

Same change, other sizes

One other searched pair makes the same change in diameter, width and sidewall:

• 215/55R17 vs 225/55R17

Other comparisons with these sizes

• 275/55R20 vs 275/60R20
• 265/50R20 vs 275/55R20

Compare other sizes in the calculator