235/35R18 tire size in inches

A 235/35R18 tire measures

24.5" tall × 9.3" wide

3.24" sidewall on a 18" wheel. 824 revolutions per mile.

235/35R18 means a tire 235 mm wide, with sidewalls 35% as tall as the tire is wide (82 mm), radial construction (R), for a 18 inch wheel.

24.5"18" rim3.2"9.3" wide
235/35R18: 24.5 inches tall, 9.3 inches wide, on a 18 inch rim, drawn to scale

235/35R18 specs

Overall diameter (height)24.48 inches (622 mm)
Section width9.25 inches (235 mm)
Sidewall height3.24 inches (82 mm)
Wheel (rim) diameter18 inches
Circumference76.9 inches (1,953 mm)
Revolutions per mile824
Revolutions per kilometer512
Approximate rim width7.5" to 9.0"
In inches (flotation style)24.5x9.3R18
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 235/35R18 on a 18" wheel

These 18" sizes are within 3% of 235/35R18's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
205/40R1824.46"8.07"−0.1%60.0 mphCompare
225/35R1824.20"8.86"−1.1%59.3 mphCompare
245/35R1824.75"9.65"+1.1%60.7 mphCompare
215/40R1824.77"8.46"+1.2%60.7 mphCompare
195/40R1824.14"7.68"−1.4%59.2 mphCompare
195/45R1824.91"7.68"+1.8%61.1 mphCompare
215/35R1823.93"8.46"−2.3%58.6 mphCompare
255/35R1825.03"10.04"+2.3%61.4 mphCompare
225/40R1825.09"8.86"+2.5%61.5 mphCompare

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

SizeWheelDiameterDifference
185/65R1515"24.47"0.0%Compare
215/50R1616"24.46"0.0%Compare
205/65R1414"24.49"+0.1%Compare
195/55R1616"24.44"−0.1%Compare
195/75R1313"24.52"+0.2%Compare
225/65R1313"24.52"+0.2%Compare
225/25R2020"24.43"−0.2%Compare
275/25R1919"24.41"−0.3%Compare
235/40R1717"24.40"−0.3%Compare
235/30R1919"24.55"+0.3%Compare
165/80R1414"24.39"−0.3%Compare
265/45R1515"24.39"−0.4%Compare

One size up or down

Compare 235/35R18 with another size

With 245/35R18 tires, when your speedometer says 60 mph you are really going

60.7 mph

245/35R18 is +0.28 inches (+1.1%) in overall diameter. That is within the 3% most shops and makers allow.

235/35R18245/35R18Difference%
Overall diameter24.48"24.75"+0.28"+1.1%
Section width9.25"9.65"+0.39"+4.3%
Sidewall height3.24"3.38"+0.14"+4.3%
Circumference76.89"77.76"+0.87"+1.1%
Revolutions per mile824.0814.8−9.2−1.1%

Questions

How tall is a 235/35R18 tire?
A 235/35R18 tire is 24.5 inches tall (622 mm), calculated from the size. It is 9.3 inches wide with 3.2 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 235/35R18 mean?
235/35R18 means a tire 235 mm wide, with sidewalls 35% as tall as the tire is wide (82 mm), radial construction (R), for a 18 inch wheel.
How many revolutions per mile does a 235/35R18 tire make?
About 824 revolutions per mile, based on a circumference of 76.9 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 235/35R18 tire?
Roughly 7.5" to 9.0". Check the tire maker's approved rim range for the exact model before buying wheels.
Can I use 205/40R18 instead of 235/35R18?
205/40R18 is −0.02 inches (−0.1%) in overall diameter, so at an indicated 60 mph you would be doing 60.0 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.

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