185/65R15 tire size in inches

A 185/65R15 tire measures

24.5" tall × 7.3" wide

4.73" sidewall on a 15" wheel. 824 revolutions per mile.

185/65R15 means a tire 185 mm wide, with sidewalls 65% as tall as the tire is wide (120 mm), radial construction (R), for a 15 inch wheel.

24.5"15" rim4.7"7.3" wide
185/65R15: 24.5 inches tall, 7.3 inches wide, on a 15 inch rim, drawn to scale

185/65R15 specs

Overall diameter (height)24.47 inches (622 mm)
Section width7.28 inches (185 mm)
Sidewall height4.73 inches (120 mm)
Wheel (rim) diameter15 inches
Circumference76.9 inches (1,952 mm)
Revolutions per mile824
Revolutions per kilometer512
Approximate rim width5.0" to 6.5"
In inches (flotation style)24.5x7.3R15
Aspect ratio65%

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 185/65R15 on a 15" wheel

These 15" sizes are within 3% of 185/65R15's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
265/45R1524.39"10.43"−0.3%59.8 mphCompare
215/55R1524.31"8.46"−0.6%59.6 mphCompare
175/70R1524.65"6.89"+0.7%60.4 mphCompare
245/50R1524.65"9.65"+0.7%60.4 mphCompare
205/60R1524.69"8.07"+0.9%60.5 mphCompare
235/50R1524.25"9.25"−0.9%59.5 mphCompare
195/60R1524.21"7.68"−1.0%59.4 mphCompare
165/75R1524.74"6.50"+1.1%60.7 mphCompare
225/55R1524.74"8.86"+1.1%60.7 mphCompare
275/45R1524.74"10.83"+1.1%60.7 mphCompare
165/70R1524.09"6.50"−1.5%59.1 mphCompare
255/45R1524.04"10.04"−1.8%58.9 mphCompare

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

SizeWheelDiameterDifference
215/50R1616"24.46"0.0%Compare
235/35R1818"24.48"0.0%Compare
205/40R1818"24.46"0.0%Compare
195/55R1616"24.44"−0.1%Compare
205/65R1414"24.49"+0.1%Compare
225/25R2020"24.43"−0.2%Compare
195/75R1313"24.52"+0.2%Compare
225/65R1313"24.52"+0.2%Compare
275/25R1919"24.41"−0.2%Compare
235/40R1717"24.40"−0.3%Compare
165/80R1414"24.39"−0.3%Compare
235/30R1919"24.55"+0.3%Compare

One size up or down

Compare 185/65R15 with another size

With 195/65R15 tires, when your speedometer says 60 mph you are really going

61.3 mph

195/65R15 is +0.51 inches (+2.1%) in overall diameter. That is within the 3% most shops and makers allow.

185/65R15195/65R15Difference%
Overall diameter24.47"24.98"+0.51"+2.1%
Section width7.28"7.68"+0.39"+5.4%
Sidewall height4.73"4.99"+0.26"+5.4%
Circumference76.87"78.48"+1.61"+2.1%
Revolutions per mile824.2807.4−16.9−2.0%

Questions

How tall is a 185/65R15 tire?
A 185/65R15 tire is 24.5 inches tall (622 mm), calculated from the size. It is 7.3 inches wide with 4.7 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 185/65R15 mean?
185/65R15 means a tire 185 mm wide, with sidewalls 65% as tall as the tire is wide (120 mm), radial construction (R), for a 15 inch wheel.
How many revolutions per mile does a 185/65R15 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 185/65R15 tire?
Roughly 5.0" to 6.5". Check the tire maker's approved rim range for the exact model before buying wheels.
Can I use 265/45R15 instead of 185/65R15?
265/45R15 is −0.08 inches (−0.3%) in overall diameter, so at an indicated 60 mph you would be doing 59.8 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.

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