255/35R21 tire size

A 255/35R21 tire is 28.03 in (711.9 mm) tall and 10.04 in (255.0 mm) wide, and turns 720 revolutions per mile.

255/35R21 dimensions
MeasurementInchesMillimeters
Overall diameter28.03 in711.9 mm
Section width10.04 in255.0 mm
Sidewall height3.51 in89.3 mm
Rim diameter21.00 in533.4 mm
Circumference88.05 in2,236 mm
Revolutions per mile720
Flotation equivalent28.0x10.0R21 (approx.)

255/35R21 is a 21-inch tire with a 255 mm (10.04 in) section width and a 35% aspect ratio, giving a 3.51-inch sidewall and a flotation-style size of about 28.0x10.0R21.

Its overall diameter is 28.03 inches, so it rolls 88.1 inches per revolution and turns about 720 times per mile.

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

Compare 255/35R21 with plausible swaps

Sizes within 3% of 28.03 in diameter

Open 255/35R21 in the tire size calculator

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