285/85R15 tire size in inches

A 285/85R15 tire measures

34.1" tall × 11.2" wide

9.54" sidewall on a 15" wheel. 592 revolutions per mile.

285/85R15 means a tire 285 mm wide, with sidewalls 85% as tall as the tire is wide (242 mm), radial construction (R), for a 15 inch wheel.

34.1"15" rim9.5"11.2" wide
285/85R15: 34.1 inches tall, 11.2 inches wide, on a 15 inch rim, drawn to scale

285/85R15 specs

Overall diameter (height)34.07 inches (865 mm)
Section width11.22 inches (285 mm)
Sidewall height9.54 inches (242 mm)
Wheel (rim) diameter15 inches
Circumference107.0 inches (2,719 mm)
Revolutions per mile592
Revolutions per kilometer368
Approximate rim width7.5" to 9.0"
In inches (flotation style)34.1x11.2R15
Aspect ratio85%

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 285/85R15 on a 15" wheel

These 15" sizes are within 3% of 285/85R15's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
275/85R1533.41"10.83"−2.0%58.8 mphCompare
35x12.50R1535.00"12.50"+2.7%61.6 mphCompare

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

SizeWheelDiameterDifference
275/65R2020"34.07"0.0%Compare
325/55R2020"34.07"0.0%Compare
295/65R1919"34.10"+0.1%Compare
315/65R1818"34.12"+0.1%Compare
305/50R2222"34.01"−0.2%Compare
355/50R2020"33.98"−0.3%Compare
335/50R2121"34.19"+0.3%Compare
285/80R1616"33.95"−0.4%Compare
345/55R1919"33.94"−0.4%Compare
305/55R2121"34.21"+0.4%Compare
295/60R2020"33.94"−0.4%Compare
345/45R2222"34.22"+0.4%Compare

One size up or down

Compare 285/85R15 with another size

With 275/85R15 tires, when your speedometer says 60 mph you are really going

58.8 mph

275/85R15 is −0.67 inches (−2.0%) in overall diameter. That is within the 3% most shops and makers allow.

285/85R15275/85R15Difference%
Overall diameter34.07"33.41"−0.67"−2.0%
Section width11.22"10.83"−0.39"−3.5%
Sidewall height9.54"9.20"−0.33"−3.5%
Circumference107.05"104.95"−2.10"−2.0%
Revolutions per mile591.9603.7+11.9+2.0%

Questions

How tall is a 285/85R15 tire?
A 285/85R15 tire is 34.1 inches tall (865 mm), calculated from the size. It is 11.2 inches wide with 9.5 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 285/85R15 mean?
285/85R15 means a tire 285 mm wide, with sidewalls 85% as tall as the tire is wide (242 mm), radial construction (R), for a 15 inch wheel.
How many revolutions per mile does a 285/85R15 tire make?
About 592 revolutions per mile, based on a circumference of 107.0 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 285/85R15 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 275/85R15 instead of 285/85R15?
275/85R15 is −0.67 inches (−2.0%) in overall diameter, so at an indicated 60 mph you would be doing 58.8 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.

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