255/35R18 Tire Size in Inches

25.0" tall, 10.0" wide, 3.5" sidewall

Diameter25.0"636 mm
Overall diameter25.0"636 mm
Section width10.0"255 mm
Sidewall height3.5"89 mm
Circumference78.6"1997 mm
Revolutions per mile806501 per km
Wheel diameter18"≈ 25.0x10.0R18 in inches

A 255/35R18 tire is 25.0 inches (636 mm) tall and 10.0 inches wide. The sidewall is 35% of the width, 3.5 inches, on a 18-inch wheel, and the tire turns about 806 times per mile.

In flotation terms that is about 25.0x10.0R18. People often call it a 25-inch tire.

The size most often compared with it is 255/40R18, which is 1.0" taller (+4.0%). At an indicated 60 mph you would be doing 62.4 mph on it, more than the 3% change many shops use as a limit.

255/35R18
255/40R18
Diameter difference+4.01%diameter 25.03" → 26.03"
CurrentNew
CurrentNewDifference

Speedometer

ShowsActual speed

Gear ratio to match

–enter your current axle ratio

Sizes near 255/35R18

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

SizeDiameterWidthSidewallvs 255/35R18
265/35R1825.3"10.4"3.7"+1.1%compare
275/30R1824.5"10.8"3.2"−2.1%
275/35R1825.6"10.8"3.8"+2.2%
255/40R1826.0"10.0"4.0"+4.0%compare
265/40R1826.3"10.4"4.2"+5.3%
275/40R1826.7"10.8"4.3"+6.5%
255/45R1827.0"10.0"4.5"+8.0%
275/45R1827.7"10.8"4.9"+10.9%

Same height on a different wheel

Sizes within 2% of 25.0" on 17" or 16" or 20" wheels.

SizeDiameterWidthSidewallvs 255/35R18
255/40R1725.0"10.0"4.0"+0.0%
185/55R1725.0"7.3"4.0"−0.1%
225/50R1624.9"8.9"4.4"−0.7%
225/30R2025.3"8.9"2.7"+1.1%
245/40R1724.7"9.6"3.9"−1.2%
275/35R1724.6"10.8"3.8"−1.8%

Speedometer with a different size

Actual speed when the speedometer is calibrated for 255/35R18.

Speedometer showson 255/40R18on 265/35R18on 275/30R18
30 mph31.2 mph30.3 mph29.4 mph
45 mph46.8 mph45.5 mph44.0 mph
60 mph62.4 mph60.7 mph58.7 mph
70 mph72.8 mph70.8 mph68.5 mph

255/35R18 comparisons

255/35R18 FAQ

How tall is a 255/35R18 tire?

25.0 inches (636 mm). The sidewall is 3.5 inches.

How wide is a 255/35R18 tire?

10.0 inches (255 mm) section width, measured sidewall to sidewall.

What is 255/35R18 in flotation size?

About 25.0x10.0R18.

Can I use 255/40R18 instead of 255/35R18?

255/40R18 is +4.0% in diameter, more than the common 3% guideline, so expect a speedometer error and check clearance. It is 0.0" wider.