225/30R20 tire size in inches

A 225/30R20 tire measures

25.3" tall × 8.9" wide

2.66" sidewall on a 20" wheel. 797 revolutions per mile.

225/30R20 means a tire 225 mm wide, with sidewalls 30% as tall as the tire is wide (68 mm), radial construction (R), for a 20 inch wheel.

25.3"20" rim2.7"8.9" wide
225/30R20: 25.3 inches tall, 8.9 inches wide, on a 20 inch rim, drawn to scale

225/30R20 specs

Overall diameter (height)25.31 inches (643 mm)
Section width8.86 inches (225 mm)
Sidewall height2.66 inches (68 mm)
Wheel (rim) diameter20 inches
Circumference79.5 inches (2,020 mm)
Revolutions per mile797
Revolutions per kilometer495
Approximate rim width7.5" to 9.0"
In inches (flotation style)25.3x8.9R20
Aspect ratio30%

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 225/30R20 on a 20" wheel

These 20" sizes are within 3% of 225/30R20's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
265/25R2025.22"10.43"−0.4%59.8 mphCompare
275/25R2025.41"10.83"+0.4%60.2 mphCompare
215/30R2025.08"8.46"−0.9%59.4 mphCompare
235/30R2025.55"9.25"+0.9%60.6 mphCompare
255/25R2025.02"10.04"−1.2%59.3 mphCompare
285/25R2025.61"11.22"+1.2%60.7 mphCompare
245/30R2025.79"9.65"+1.9%61.1 mphCompare
245/25R2024.82"9.65"−1.9%58.8 mphCompare
295/25R2025.81"11.61"+1.9%61.2 mphCompare
215/35R2025.93"8.46"+2.4%61.4 mphCompare
235/25R2024.63"9.25"−2.7%58.4 mphCompare
305/25R2026.00"12.01"+2.7%61.6 mphCompare

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

SizeWheelDiameterDifference
215/55R1616"25.31"0.0%Compare
265/35R1818"25.30"0.0%Compare
235/45R1717"25.33"0.0%Compare
205/70R1414"25.30"−0.1%Compare
175/75R1515"25.33"+0.1%Compare
295/40R1616"25.29"−0.1%Compare
195/80R1313"25.28"−0.1%Compare
265/40R1717"25.35"+0.1%Compare
205/45R1818"25.26"−0.2%Compare
265/30R1919"25.26"−0.2%Compare
235/50R1616"25.25"−0.2%Compare
185/85R1313"25.38"+0.3%Compare

One size up or down

Compare 225/30R20 with another size

With 235/30R20 tires, when your speedometer says 60 mph you are really going

60.6 mph

235/30R20 is +0.24 inches (+0.9%) in overall diameter. That is within the 3% most shops and makers allow.

225/30R20235/30R20Difference%
Overall diameter25.31"25.55"+0.24"+0.9%
Section width8.86"9.25"+0.39"+4.4%
Sidewall height2.66"2.78"+0.12"+4.4%
Circumference79.53"80.27"+0.74"+0.9%
Revolutions per mile796.7789.3−7.4−0.9%

Questions

How tall is a 225/30R20 tire?
A 225/30R20 tire is 25.3 inches tall (643 mm), calculated from the size. It is 8.9 inches wide with 2.7 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 225/30R20 mean?
225/30R20 means a tire 225 mm wide, with sidewalls 30% as tall as the tire is wide (68 mm), radial construction (R), for a 20 inch wheel.
How many revolutions per mile does a 225/30R20 tire make?
About 797 revolutions per mile, based on a circumference of 79.5 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 225/30R20 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 265/25R20 instead of 225/30R20?
265/25R20 is −0.10 inches (−0.4%) 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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