285/50R18 Tire Size in Inches

29.2" tall, 11.2" wide, 5.6" sidewall

Diameter29.2"742 mm
Overall diameter29.2"742 mm
Section width11.2"285 mm
Sidewall height5.6"143 mm
Circumference91.8"2332 mm
Revolutions per mile690429 per km
Wheel diameter18"≈ 29.2x11.2R18 in inches

A 285/50R18 tire is 29.2 inches (742 mm) tall and 11.2 inches wide. The sidewall is 50% of the width, 5.6 inches, on a 18-inch wheel, and the tire turns about 690 times per mile.

In flotation terms that is about 29.2x11.2R18. People often call it a 29-inch tire.

The size most often compared with it is 265/55R18, which is 0.3" taller (+0.9%). At an indicated 60 mph you would be doing 60.5 mph on it.

285/50R18
265/55R18
Diameter difference+0.88%diameter 29.22" → 29.48"
CurrentNew
CurrentNewDifference

Speedometer

ShowsActual speed

Gear ratio to match

–enter your current axle ratio

Sizes near 285/50R18

Same 18" wheel, within 20 mm of width and 10 points of aspect ratio.

SizeDiameterWidthSidewallvs 285/50R18
265/55R1829.5"10.4"5.7"+0.9%
275/50R1828.8"10.8"5.4"−1.3%
275/55R1829.9"10.8"6.0"+2.4%
295/45R1828.5"11.6"5.2"−2.6%
265/50R1828.4"10.4"5.2"−2.7%
285/45R1828.1"11.2"5.0"−3.8%
285/55R1830.3"11.2"6.2"+3.8%
275/45R1827.7"10.8"4.9"−5.1%
295/55R1830.8"11.6"6.4"+5.3%
275/60R1831.0"10.8"6.5"+6.1%

Same height on a different wheel

Sizes within 2% of 29.2" on 16" or 20" or 17" wheels.

SizeDiameterWidthSidewallvs 285/50R18
225/75R1629.3"8.9"6.6"+0.2%
295/40R2029.3"11.6"4.6"+0.2%
285/55R1729.3"11.2"6.2"+0.4%
225/70R1729.4"8.9"6.2"+0.6%
315/50R1729.4"12.4"6.2"+0.6%
275/60R1629.0"10.8"6.5"−0.8%

Speedometer with a different size

Actual speed when the speedometer is calibrated for 285/50R18.

Speedometer showson 265/55R18on 275/50R18on 275/55R18
30 mph30.3 mph29.6 mph30.7 mph
45 mph45.4 mph44.4 mph46.1 mph
60 mph60.5 mph59.2 mph61.4 mph
70 mph70.6 mph69.1 mph71.7 mph

285/50R18 FAQ

How tall is a 285/50R18 tire?

29.2 inches (742 mm). The sidewall is 5.6 inches.

How wide is a 285/50R18 tire?

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

What is 285/50R18 in flotation size?

About 29.2x11.2R18.

Can I use 265/55R18 instead of 285/50R18?

265/55R18 is +0.9% in diameter, within the common 3% guideline. It is 0.8" narrower.