285/35R18 tire size in inches

A 285/35R18 tire measures

25.9" tall × 11.2" wide

3.93" sidewall on a 18" wheel. 780 revolutions per mile.

285/35R18 means a tire 285 mm wide, with sidewalls 35% as tall as the tire is wide (100 mm), radial construction (R), for a 18 inch wheel.

25.9"18" rim3.9"11.2" wide
285/35R18: 25.9 inches tall, 11.2 inches wide, on a 18 inch rim, drawn to scale

285/35R18 specs

Overall diameter (height)25.85 inches (657 mm)
Section width11.22 inches (285 mm)
Sidewall height3.93 inches (100 mm)
Wheel (rim) diameter18 inches
Circumference81.2 inches (2,063 mm)
Revolutions per mile780
Revolutions per kilometer485
Approximate rim width9.5" to 11.0"
In inches (flotation style)25.9x11.2R18
Aspect ratio35%

Calculated from the size. Real tires differ by brand, model and tread depth, typically by a few tenths of an inch.

Sizes that can replace 285/35R18 on a 18" wheel

These 18" sizes are within 3% of 285/35R18's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
225/45R1825.97"8.86"+0.5%60.3 mphCompare
245/40R1825.72"9.65"−0.5%59.7 mphCompare
195/50R1825.68"7.68"−0.7%59.6 mphCompare
255/40R1826.03"10.04"+0.7%60.4 mphCompare
205/50R1826.07"8.07"+0.8%60.5 mphCompare
215/45R1825.62"8.46"−0.9%59.5 mphCompare
295/35R1826.13"11.61"+1.1%60.6 mphCompare
275/35R1825.58"10.83"−1.1%59.4 mphCompare
235/40R1825.40"9.25"−1.8%58.9 mphCompare
235/45R1826.33"9.25"+1.8%61.1 mphCompare
265/40R1826.35"10.43"+1.9%61.1 mphCompare
265/35R1825.30"10.43"−2.1%58.7 mphCompare

Same height on other wheel sizes (plus and minus sizing)

SizeWheelDiameterDifference
225/50R1717"25.86"0.0%Compare
215/70R1414"25.85"0.0%Compare
205/55R1717"25.88"+0.1%Compare
275/50R1515"25.83"−0.1%Compare
245/25R2121"25.82"−0.1%Compare
295/25R2020"25.81"−0.2%Compare
205/80R1313"25.91"+0.2%Compare
345/25R1919"25.79"−0.2%Compare
245/30R2020"25.79"−0.3%Compare
215/35R2020"25.93"+0.3%Compare
185/75R1515"25.93"+0.3%Compare
215/40R1919"25.77"−0.3%Compare

One size up or down

Compare 285/35R18 with another size

With 295/35R18 tires, when your speedometer says 60 mph you are really going

60.6 mph

295/35R18 is +0.28 inches (+1.1%) in overall diameter. That is within the 3% most shops and makers allow.

285/35R18295/35R18Difference%
Overall diameter25.85"26.13"+0.28"+1.1%
Section width11.22"11.61"+0.39"+3.5%
Sidewall height3.93"4.06"+0.14"+3.5%
Circumference81.22"82.09"+0.87"+1.1%
Revolutions per mile780.1771.8−8.2−1.1%

Questions

How tall is a 285/35R18 tire?
A 285/35R18 tire is 25.9 inches tall (657 mm), calculated from the size. It is 11.2 inches wide with 3.9 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 285/35R18 mean?
285/35R18 means a tire 285 mm wide, with sidewalls 35% as tall as the tire is wide (100 mm), radial construction (R), for a 18 inch wheel.
How many revolutions per mile does a 285/35R18 tire make?
About 780 revolutions per mile, based on a circumference of 81.2 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 285/35R18 tire?
Roughly 9.5" to 11.0". Check the tire maker's approved rim range for the exact model before buying wheels.
Can I use 225/45R18 instead of 285/35R18?
225/45R18 is +0.12 inches (+0.5%) in overall diameter, so at an indicated 60 mph you would be doing 60.3 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.

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