285/65R20 tire size in inches

A 285/65R20 tire measures

34.6" tall × 11.2" wide

7.29" sidewall on a 20" wheel. 583 revolutions per mile.

285/65R20 means a tire 285 mm wide, with sidewalls 65% as tall as the tire is wide (185 mm), radial construction (R), for a 20 inch wheel.

34.6"20" rim7.3"11.2" wide
285/65R20: 34.6 inches tall, 11.2 inches wide, on a 20 inch rim, drawn to scale

285/65R20 specs

Overall diameter (height)34.59 inches (879 mm)
Section width11.22 inches (285 mm)
Sidewall height7.29 inches (185 mm)
Wheel (rim) diameter20 inches
Circumference108.7 inches (2,760 mm)
Revolutions per mile583
Revolutions per kilometer362
Approximate rim width7.5" to 9.0"
In inches (flotation style)34.6x11.2R20
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 285/65R20 on a 20" wheel

These 20" sizes are within 3% of 285/65R20's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
335/55R2034.51"13.19"−0.2%59.9 mphCompare
305/60R2034.41"12.01"−0.5%59.7 mphCompare
315/60R2034.88"12.40"+0.9%60.5 mphCompare
345/55R2034.94"13.58"+1.0%60.6 mphCompare
35x12.50R2035.00"12.50"+1.2%60.7 mphCompare
295/65R2035.10"11.61"+1.5%60.9 mphCompare
275/65R2034.07"10.83"−1.5%59.1 mphCompare
325/55R2034.07"12.80"−1.5%59.1 mphCompare
355/50R2033.98"13.98"−1.8%58.9 mphCompare
295/60R2033.94"11.61"−1.9%58.9 mphCompare
325/60R2035.35"12.80"+2.2%61.3 mphCompare
355/55R2035.37"13.98"+2.3%61.4 mphCompare

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

SizeWheelDiameterDifference
295/80R1616"34.58"0.0%Compare
345/50R2121"34.58"0.0%Compare
355/45R2222"34.58"0.0%Compare
305/65R1919"34.61"+0.1%Compare
335/40R2424"34.55"−0.1%Compare
325/65R1818"34.63"+0.1%Compare
315/55R2121"34.64"+0.2%Compare
295/75R1717"34.42"−0.5%Compare
275/85R1616"34.41"−0.5%Compare
315/50R2222"34.40"−0.5%Compare
295/55R2222"34.78"+0.5%Compare
325/50R2222"34.80"+0.6%Compare

One size up or down

Compare 285/65R20 with another size

With 295/65R20 tires, when your speedometer says 60 mph you are really going

60.9 mph

295/65R20 is +0.51 inches (+1.5%) in overall diameter. That is within the 3% most shops and makers allow.

285/65R20295/65R20Difference%
Overall diameter34.59"35.10"+0.51"+1.5%
Section width11.22"11.61"+0.39"+3.5%
Sidewall height7.29"7.55"+0.26"+3.5%
Circumference108.66"110.26"+1.61"+1.5%
Revolutions per mile583.1574.6−8.5−1.5%

Questions

How tall is a 285/65R20 tire?
A 285/65R20 tire is 34.6 inches tall (879 mm), calculated from the size. It is 11.2 inches wide with 7.3 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 285/65R20 mean?
285/65R20 means a tire 285 mm wide, with sidewalls 65% as tall as the tire is wide (185 mm), radial construction (R), for a 20 inch wheel.
How many revolutions per mile does a 285/65R20 tire make?
About 583 revolutions per mile, based on a circumference of 108.7 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 285/65R20 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 335/55R20 instead of 285/65R20?
335/55R20 is −0.08 inches (−0.2%) in overall diameter, so at an indicated 60 mph you would be doing 59.9 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.

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