285/50R21 tire size in inches

A 285/50R21 tire measures

32.2" tall × 11.2" wide

5.61" sidewall on a 21" wheel. 626 revolutions per mile.

285/50R21 means a tire 285 mm wide, with sidewalls 50% as tall as the tire is wide (143 mm), radial construction (R), for a 21 inch wheel.

32.2"21" rim5.6"11.2" wide
285/50R21: 32.2 inches tall, 11.2 inches wide, on a 21 inch rim, drawn to scale

285/50R21 specs

Overall diameter (height)32.22 inches (818 mm)
Section width11.22 inches (285 mm)
Sidewall height5.61 inches (143 mm)
Wheel (rim) diameter21 inches
Circumference101.2 inches (2,571 mm)
Revolutions per mile626
Revolutions per kilometer389
Approximate rim width8.0" to 9.5"
In inches (flotation style)32.2x11.2R21
Aspect ratio50%

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 285/50R21 on a 21" wheel

These 21" sizes are within 3% of 285/50R21's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
355/40R2132.18"13.98"−0.1%59.9 mphCompare
315/45R2132.16"12.40"−0.2%59.9 mphCompare
255/55R2132.04"10.04"−0.5%59.7 mphCompare
265/55R2132.48"10.43"+0.8%60.5 mphCompare
325/45R2132.52"12.80"+0.9%60.5 mphCompare
345/40R2131.87"13.58"−1.1%59.3 mphCompare
275/50R2131.83"10.83"−1.2%59.3 mphCompare
295/50R2132.61"11.61"+1.2%60.7 mphCompare
305/45R2131.81"12.01"−1.3%59.2 mphCompare
245/55R2131.61"9.65"−1.9%58.9 mphCompare
335/45R2132.87"13.19"+2.0%61.2 mphCompare
335/40R2131.55"13.19"−2.1%58.8 mphCompare

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

SizeWheelDiameterDifference
345/45R2020"32.22"0.0%Compare
305/55R1919"32.21"0.0%Compare
325/40R2222"32.24"0.0%Compare
275/75R1616"32.24"+0.1%Compare
335/50R1919"32.19"−0.1%Compare
295/70R1616"32.26"+0.1%Compare
235/55R2222"32.18"−0.1%Compare
275/70R1717"32.16"−0.2%Compare
345/30R2424"32.15"−0.2%Compare
295/35R2424"32.13"−0.3%Compare
275/80R1515"32.32"+0.3%Compare
285/55R2020"32.34"+0.4%Compare

One size up or down

Compare 285/50R21 with another size

With 295/50R21 tires, when your speedometer says 60 mph you are really going

60.7 mph

295/50R21 is +0.39 inches (+1.2%) in overall diameter. That is within the 3% most shops and makers allow.

285/50R21295/50R21Difference%
Overall diameter32.22"32.61"+0.39"+1.2%
Section width11.22"11.61"+0.39"+3.5%
Sidewall height5.61"5.81"+0.20"+3.5%
Circumference101.22"102.46"+1.24"+1.2%
Revolutions per mile625.9618.4−7.6−1.2%

Questions

How tall is a 285/50R21 tire?
A 285/50R21 tire is 32.2 inches tall (818 mm), calculated from the size. It is 11.2 inches wide with 5.6 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 285/50R21 mean?
285/50R21 means a tire 285 mm wide, with sidewalls 50% as tall as the tire is wide (143 mm), radial construction (R), for a 21 inch wheel.
How many revolutions per mile does a 285/50R21 tire make?
About 626 revolutions per mile, based on a circumference of 101.2 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 285/50R21 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 355/40R21 instead of 285/50R21?
355/40R21 is −0.04 inches (−0.1%) 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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