355/50R21 tire size in inches

A 355/50R21 tire measures

35.0" tall × 14.0" wide

6.99" sidewall on a 21" wheel. 577 revolutions per mile.

355/50R21 means a tire 355 mm wide, with sidewalls 50% as tall as the tire is wide (178 mm), radial construction (R), for a 21 inch wheel.

35.0"21" rim7.0"14.0" wide
355/50R21: 35.0 inches tall, 14.0 inches wide, on a 21 inch rim, drawn to scale

355/50R21 specs

Overall diameter (height)34.98 inches (888 mm)
Section width13.98 inches (355 mm)
Sidewall height6.99 inches (178 mm)
Wheel (rim) diameter21 inches
Circumference109.9 inches (2,791 mm)
Revolutions per mile577
Revolutions per kilometer358
Approximate rim width10.0" to 11.5"
In inches (flotation style)35.0x14.0R21
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 355/50R21 on a 21" wheel

These 21" sizes are within 3% of 355/50R21's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
325/55R2135.07"12.80"+0.3%60.2 mphCompare
315/55R2134.64"12.40"−1.0%59.4 mphCompare
345/50R2134.58"13.58"−1.1%59.3 mphCompare
335/55R2135.51"13.19"+1.5%60.9 mphCompare
305/55R2134.21"12.01"−2.2%58.7 mphCompare
335/50R2134.19"13.19"−2.3%58.6 mphCompare
345/55R2135.94"13.58"+2.8%61.7 mphCompare

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

SizeWheelDiameterDifference
35x12.50R1515"35.00"+0.1%Compare
35x12.50R1717"35.00"+0.1%Compare
35x12.50R1818"35.00"+0.1%Compare
35x12.50R2020"35.00"+0.1%Compare
35x12.50R2222"35.00"+0.1%Compare
35x12.50R2424"35.00"+0.1%Compare
305/75R1717"35.01"+0.1%Compare
345/55R2020"34.94"−0.1%Compare
315/60R2020"34.88"−0.3%Compare
285/85R1616"35.07"+0.3%Compare
345/40R2424"34.87"−0.3%Compare
295/65R2020"35.10"+0.3%Compare

One size up or down

Compare 355/50R21 with another size

With 325/55R21 tires, when your speedometer says 60 mph you are really going

60.2 mph

325/55R21 is +0.10 inches (+0.3%) in overall diameter. That is within the 3% most shops and makers allow.

355/50R21325/55R21Difference%
Overall diameter34.98"35.07"+0.10"+0.3%
Section width13.98"12.80"−1.18"−8.5%
Sidewall height6.99"7.04"+0.05"+0.7%
Circumference109.88"110.19"+0.31"+0.3%
Revolutions per mile576.6575.0−1.6−0.3%

Questions

How tall is a 355/50R21 tire?
A 355/50R21 tire is 35.0 inches tall (888 mm), calculated from the size. It is 14.0 inches wide with 7.0 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 355/50R21 mean?
355/50R21 means a tire 355 mm wide, with sidewalls 50% as tall as the tire is wide (178 mm), radial construction (R), for a 21 inch wheel.
How many revolutions per mile does a 355/50R21 tire make?
About 577 revolutions per mile, based on a circumference of 109.9 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 355/50R21 tire?
Roughly 10.0" to 11.5". Check the tire maker's approved rim range for the exact model before buying wheels.
Can I use 325/55R21 instead of 355/50R21?
325/55R21 is +0.10 inches (+0.3%) in overall diameter, so at an indicated 60 mph you would be doing 60.2 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.

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