305/30R24 tire size in inches

A 305/30R24 tire measures

31.2" tall × 12.0" wide

3.60" sidewall on a 24" wheel. 646 revolutions per mile.

305/30R24 means a tire 305 mm wide, with sidewalls 30% as tall as the tire is wide (92 mm), radial construction (R), for a 24 inch wheel.

31.2"24" rim3.6"12.0" wide
305/30R24: 31.2 inches tall, 12.0 inches wide, on a 24 inch rim, drawn to scale

305/30R24 specs

Overall diameter (height)31.20 inches (793 mm)
Section width12.01 inches (305 mm)
Sidewall height3.60 inches (92 mm)
Wheel (rim) diameter24 inches
Circumference98.0 inches (2,490 mm)
Revolutions per mile646
Revolutions per kilometer402
Approximate rim width10.0" to 11.5"
In inches (flotation style)31.2x12.0R24
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 305/30R24 on a 24" wheel

These 24" sizes are within 3% of 305/30R24's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
265/35R2431.30"10.43"+0.3%60.2 mphCompare
255/35R2431.03"10.04"−0.6%59.7 mphCompare
355/25R2430.99"13.98"−0.7%59.6 mphCompare
295/30R2430.97"11.61"−0.8%59.5 mphCompare
315/30R2431.44"12.40"+0.8%60.5 mphCompare
275/35R2431.58"10.83"+1.2%60.7 mphCompare
345/25R2430.79"13.58"−1.3%59.2 mphCompare
285/30R2430.73"11.22"−1.5%59.1 mphCompare
325/30R2431.68"12.80"+1.5%60.9 mphCompare
335/25R2430.59"13.19"−2.0%58.8 mphCompare
285/35R2431.85"11.22"+2.1%61.2 mphCompare
275/30R2430.50"10.83"−2.3%58.6 mphCompare

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

SizeWheelDiameterDifference
305/55R1818"31.21"0.0%Compare
285/50R2020"31.22"+0.1%Compare
335/50R1818"31.19"−0.1%Compare
345/45R1919"31.22"+0.1%Compare
355/40R2020"31.18"−0.1%Compare
235/55R2121"31.18"−0.1%Compare
335/35R2222"31.23"+0.1%Compare
325/40R2121"31.24"+0.1%Compare
275/75R1515"31.24"+0.1%Compare
315/45R2020"31.16"−0.1%Compare
235/50R2222"31.25"+0.2%Compare
275/70R1616"31.16"−0.2%Compare

One size up or down

Compare 305/30R24 with another size

With 315/30R24 tires, when your speedometer says 60 mph you are really going

60.5 mph

315/30R24 is +0.24 inches (+0.8%) in overall diameter. That is within the 3% most shops and makers allow.

305/30R24315/30R24Difference%
Overall diameter31.20"31.44"+0.24"+0.8%
Section width12.01"12.40"+0.39"+3.3%
Sidewall height3.60"3.72"+0.12"+3.3%
Circumference98.03"98.77"+0.74"+0.8%
Revolutions per mile646.3641.5−4.9−0.8%

Questions

How tall is a 305/30R24 tire?
A 305/30R24 tire is 31.2 inches tall (793 mm), calculated from the size. It is 12.0 inches wide with 3.6 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 305/30R24 mean?
305/30R24 means a tire 305 mm wide, with sidewalls 30% as tall as the tire is wide (92 mm), radial construction (R), for a 24 inch wheel.
How many revolutions per mile does a 305/30R24 tire make?
About 646 revolutions per mile, based on a circumference of 98.0 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 305/30R24 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 265/35R24 instead of 305/30R24?
265/35R24 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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