185/45R17 tire size in inches

A 185/45R17 tire measures

23.6" tall × 7.3" wide

3.28" sidewall on a 17" wheel. 856 revolutions per mile.

185/45R17 means a tire 185 mm wide, with sidewalls 45% as tall as the tire is wide (83 mm), radial construction (R), for a 17 inch wheel.

23.6"17" rim3.3"7.3" wide
185/45R17: 23.6 inches tall, 7.3 inches wide, on a 17 inch rim, drawn to scale

185/45R17 specs

Overall diameter (height)23.56 inches (598 mm)
Section width7.28 inches (185 mm)
Sidewall height3.28 inches (83 mm)
Wheel (rim) diameter17 inches
Circumference74.0 inches (1,880 mm)
Revolutions per mile856
Revolutions per kilometer532
Approximate rim width6.0" to 7.5"
In inches (flotation style)23.6x7.3R17
Aspect ratio45%

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 185/45R17 on a 17" wheel

These 17" sizes are within 3% of 185/45R17's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
235/35R1723.48"9.25"−0.3%59.8 mphCompare
205/40R1723.46"8.07"−0.4%59.7 mphCompare
245/35R1723.75"9.65"+0.8%60.5 mphCompare
215/40R1723.77"8.46"+0.9%60.6 mphCompare
195/45R1723.91"7.68"+1.5%60.9 mphCompare
225/35R1723.20"8.86"−1.5%59.1 mphCompare
195/40R1723.14"7.68"−1.8%58.9 mphCompare
255/35R1724.03"10.04"+2.0%61.2 mphCompare
225/40R1724.09"8.86"+2.3%61.4 mphCompare
215/35R1722.93"8.46"−2.7%58.4 mphCompare

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

SizeWheelDiameterDifference
175/55R1616"23.58"+0.1%Compare
205/65R1313"23.49"−0.3%Compare
215/45R1616"23.62"+0.3%Compare
235/25R1919"23.63"+0.3%Compare
225/60R1313"23.63"+0.3%Compare
185/65R1414"23.47"−0.4%Compare
175/70R1414"23.65"+0.4%Compare
215/50R1515"23.46"−0.4%Compare
205/35R1818"23.65"+0.4%Compare
165/65R1515"23.44"−0.5%Compare
195/55R1515"23.44"−0.5%Compare
195/50R1616"23.68"+0.5%Compare

One size up or down

Compare 185/45R17 with another size

With 195/45R17 tires, when your speedometer says 60 mph you are really going

60.9 mph

195/45R17 is +0.35 inches (+1.5%) in overall diameter. That is within the 3% most shops and makers allow.

185/45R17195/45R17Difference%
Overall diameter23.56"23.91"+0.35"+1.5%
Section width7.28"7.68"+0.39"+5.4%
Sidewall height3.28"3.45"+0.18"+5.4%
Circumference74.00"75.11"+1.11"+1.5%
Revolutions per mile856.2843.5−12.7−1.5%

Questions

How tall is a 185/45R17 tire?
A 185/45R17 tire is 23.6 inches tall (598 mm), calculated from the size. It is 7.3 inches wide with 3.3 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 185/45R17 mean?
185/45R17 means a tire 185 mm wide, with sidewalls 45% as tall as the tire is wide (83 mm), radial construction (R), for a 17 inch wheel.
How many revolutions per mile does a 185/45R17 tire make?
About 856 revolutions per mile, based on a circumference of 74.0 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 185/45R17 tire?
Roughly 6.0" to 7.5". Check the tire maker's approved rim range for the exact model before buying wheels.
Can I use 235/35R17 instead of 185/45R17?
235/35R17 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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