245/35R18 tire size in inches

A 245/35R18 tire measures

24.8" tall × 9.6" wide

3.38" sidewall on a 18" wheel. 815 revolutions per mile.

245/35R18 means a tire 245 mm wide, with sidewalls 35% as tall as the tire is wide (86 mm), radial construction (R), for a 18 inch wheel.

24.8"18" rim3.4"9.6" wide
245/35R18: 24.8 inches tall, 9.6 inches wide, on a 18 inch rim, drawn to scale

245/35R18 specs

Overall diameter (height)24.75 inches (629 mm)
Section width9.65 inches (245 mm)
Sidewall height3.38 inches (86 mm)
Wheel (rim) diameter18 inches
Circumference77.8 inches (1,975 mm)
Revolutions per mile815
Revolutions per kilometer506
Approximate rim width8.0" to 9.5"
In inches (flotation style)24.8x9.6R18
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 245/35R18 on a 18" wheel

These 18" sizes are within 3% of 245/35R18's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
215/40R1824.77"8.46"+0.1%60.0 mphCompare
195/45R1824.91"7.68"+0.6%60.4 mphCompare
235/35R1824.48"9.25"−1.1%59.3 mphCompare
255/35R1825.03"10.04"+1.1%60.7 mphCompare
205/40R1824.46"8.07"−1.2%59.3 mphCompare
225/40R1825.09"8.86"+1.4%60.8 mphCompare
205/45R1825.26"8.07"+2.1%61.2 mphCompare
225/35R1824.20"8.86"−2.2%58.7 mphCompare
265/35R1825.30"10.43"+2.2%61.3 mphCompare
195/40R1824.14"7.68"−2.5%58.5 mphCompare
235/40R1825.40"9.25"+2.6%61.6 mphCompare

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

SizeWheelDiameterDifference
195/70R1414"24.75"0.0%Compare
165/75R1515"24.74"0.0%Compare
225/55R1515"24.74"0.0%Compare
275/45R1515"24.74"0.0%Compare
185/60R1616"24.74"0.0%Compare
245/40R1717"24.72"−0.1%Compare
245/30R1919"24.79"+0.1%Compare
175/85R1313"24.71"−0.2%Compare
295/25R1919"24.81"+0.2%Compare
205/60R1515"24.69"−0.3%Compare
245/45R1616"24.68"−0.3%Compare
245/25R2020"24.82"+0.3%Compare

One size up or down

Compare 245/35R18 with another size

With 255/35R18 tires, when your speedometer says 60 mph you are really going

60.7 mph

255/35R18 is +0.28 inches (+1.1%) in overall diameter. That is within the 3% most shops and makers allow.

245/35R18255/35R18Difference%
Overall diameter24.75"25.03"+0.28"+1.1%
Section width9.65"10.04"+0.39"+4.1%
Sidewall height3.38"3.51"+0.14"+4.1%
Circumference77.76"78.63"+0.87"+1.1%
Revolutions per mile814.8805.8−9.0−1.1%

Questions

How tall is a 245/35R18 tire?
A 245/35R18 tire is 24.8 inches tall (629 mm), calculated from the size. It is 9.6 inches wide with 3.4 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 245/35R18 mean?
245/35R18 means a tire 245 mm wide, with sidewalls 35% as tall as the tire is wide (86 mm), radial construction (R), for a 18 inch wheel.
How many revolutions per mile does a 245/35R18 tire make?
About 815 revolutions per mile, based on a circumference of 77.8 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 245/35R18 tire?
Roughly 8.0" to 9.5". Check the tire maker's approved rim range for the exact model before buying wheels.
Can I use 215/40R18 instead of 245/35R18?
215/40R18 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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