305/40R20 tire size

A 305/40R20 tire is 29.61 in (752.0 mm) tall and 12.01 in (305.0 mm) wide, and turns 681 revolutions per mile.

305/40R20 dimensions
MeasurementInchesMillimeters
Overall diameter29.61 in752.0 mm
Section width12.01 in305.0 mm
Sidewall height4.80 in122.0 mm
Rim diameter20.00 in508.0 mm
Circumference93.01 in2,362 mm
Revolutions per mile681
Flotation equivalent29.6x12.0R20 (approx.)

305/40R20 is a 20-inch tire with a 305 mm (12.01 in) section width and a 40% aspect ratio, giving a 4.80-inch sidewall and a flotation-style size of about 29.6x12.0R20.

Its overall diameter is 29.61 inches, so it rolls 93.0 inches per revolution and turns about 681 times per mile.

72 other sizes in this list are within 3% of that diameter.

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Sizes within 3% of 29.61 in diameter

Open 305/40R20 in the tire size calculator

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.