285/35R18 Tire Size in Inches

25.9" tall, 11.2" wide, 3.9" sidewall

Diameter25.9"657 mm
Overall diameter25.9"657 mm
Section width11.2"285 mm
Sidewall height3.9"100 mm
Circumference81.2"2063 mm
Revolutions per mile780485 per km
Wheel diameter18"≈ 25.9x11.2R18 in inches

A 285/35R18 tire is 25.9 inches (657 mm) tall and 11.2 inches wide. The sidewall is 35% of the width, 3.9 inches, on a 18-inch wheel, and the tire turns about 780 times per mile.

In flotation terms that is about 25.9x11.2R18. People often call it a 26-inch tire.

The size most often compared with it is 275/35R18, which is 0.3" shorter (−1.1%). At an indicated 60 mph you would be doing 59.4 mph on it.

285/35R18
275/35R18
Diameter difference−1.07%diameter 25.85" → 25.58"
CurrentNew
CurrentNewDifference

Speedometer

ShowsActual speed

Gear ratio to match

–enter your current axle ratio

Sizes near 285/35R18

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

SizeDiameterWidthSidewallvs 285/35R18
275/35R1825.6"10.8"3.8"−1.1%
295/35R1826.1"11.6"4.1"+1.1%
265/40R1826.3"10.4"4.2"+1.9%
305/35R1826.4"12.0"4.2"+2.1%
265/35R1825.3"10.4"3.7"−2.1%
305/30R1825.2"12.0"3.6"−2.5%
275/40R1826.7"10.8"4.3"+3.1%
295/30R1825.0"11.6"3.5"−3.4%
285/30R1824.7"11.2"3.4"−4.3%
285/40R1827.0"11.2"4.5"+4.3%

Same height on a different wheel

Sizes within 2% of 25.9" on 17" or 16" or 19" wheels.

SizeDiameterWidthSidewallvs 285/35R18
285/40R1726.0"11.2"4.5"+0.5%
315/35R1725.7"12.4"4.3"−0.7%
255/45R1726.0"10.0"4.5"+0.7%
275/40R1725.7"10.8"4.3"−0.7%
245/50R1625.6"9.6"4.8"−0.8%
305/30R1926.2"12.0"3.6"+1.4%

Speedometer with a different size

Actual speed when the speedometer is calibrated for 285/35R18.

Speedometer showson 275/35R18on 295/35R18on 265/40R18
30 mph29.7 mph30.3 mph30.6 mph
45 mph44.5 mph45.5 mph45.9 mph
60 mph59.4 mph60.6 mph61.1 mph
70 mph69.3 mph70.7 mph71.3 mph

285/35R18 FAQ

How tall is a 285/35R18 tire?

25.9 inches (657 mm). The sidewall is 3.9 inches.

How wide is a 285/35R18 tire?

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

What is 285/35R18 in flotation size?

About 25.9x11.2R18.

Can I use 275/35R18 instead of 285/35R18?

275/35R18 is −1.1% in diameter, within the common 3% guideline. It is 0.4" narrower.