285/50R20 Tire Size in Inches

31.2" tall, 11.2" wide, 5.6" sidewall

Diameter31.2"793 mm
Overall diameter31.2"793 mm
Section width11.2"285 mm
Sidewall height5.6"143 mm
Circumference98.1"2491 mm
Revolutions per mile646401 per km
Wheel diameter20"≈ 31.2x11.2R20 in inches

A 285/50R20 tire is 31.2 inches (793 mm) tall and 11.2 inches wide. The sidewall is 50% of the width, 5.6 inches, on a 20-inch wheel, and the tire turns about 646 times per mile.

In flotation terms that is about 31.2x11.2R20. People often call it a 31-inch tire.

The size most often compared with it is 275/55R20, which is 0.7" taller (+2.2%). At an indicated 60 mph you would be doing 61.3 mph on it.

285/50R20
275/55R20
Diameter difference+2.21%diameter 31.22" → 31.91"
CurrentNew
CurrentNewDifference

Speedometer

ShowsActual speed

Gear ratio to match

–enter your current axle ratio

Sizes near 285/50R20

Same 20" wheel, within 20 mm of width and 10 points of aspect ratio.

SizeDiameterWidthSidewallvs 285/50R20
265/55R2031.5"10.4"5.7"+0.8%
295/50R2031.6"11.6"5.8"+1.3%
275/50R2030.8"10.8"5.4"−1.3%
305/45R2030.8"12.0"5.4"−1.3%
275/55R2031.9"10.8"6.0"+2.2%compare
295/45R2030.5"11.6"5.2"−2.5%
305/50R2032.0"12.0"6.0"+2.5%
285/55R2032.3"11.2"6.2"+3.6%
265/60R2032.5"10.4"6.3"+4.2%
295/55R2032.8"11.6"6.4"+5.0%

Same height on a different wheel

Sizes within 2% of 31.2" on 18" or 22" or 19" wheels.

SizeDiameterWidthSidewallvs 285/50R20
305/55R1831.2"12.0"6.6"−0.0%
295/40R2231.3"11.6"4.6"+0.2%
265/45R2231.4"10.4"4.7"+0.5%
225/70R1931.4"8.9"6.2"+0.6%
275/60R1831.0"10.8"6.5"−0.7%
285/60R1831.5"11.2"6.7"+0.8%

Speedometer with a different size

Actual speed when the speedometer is calibrated for 285/50R20.

Speedometer showson 275/55R20on 275/60R20on 265/55R20
30 mph30.7 mph31.7 mph30.2 mph
45 mph46.0 mph47.6 mph45.4 mph
60 mph61.3 mph63.4 mph60.5 mph
70 mph71.5 mph74.0 mph70.6 mph

285/50R20 comparisons

285/50R20 FAQ

How tall is a 285/50R20 tire?

31.2 inches (793 mm). The sidewall is 5.6 inches.

How wide is a 285/50R20 tire?

11.2 inches (285 mm) section width, measured sidewall to sidewall.

What is 285/50R20 in flotation size?

About 31.2x11.2R20.

Can I use 275/55R20 instead of 285/50R20?

275/55R20 is +2.2% in diameter, within the common 3% guideline. It is 0.4" narrower.