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255/40 R21 tire dimensions

Nominal geometric dimensions, calculated from the size marking.

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737.4 mm

Overall diameter · 255/40 R21

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What 255/40 R21 means

Nominal section width255 mm
Sidewall-to-width ratio40%
Sidewall height102 mm
ConstructionR — radial
Wheel bead-seat diameter21 inches
Overall diameter737 mm (29.0 in)
Rolling circumference2317 mm

Load index, speed rating and approved wheel widths must also match the vehicle requirements. Calculated dimensions do not establish a safe replacement size. Actual rolling circumference changes with load, pressure, wear and tire construction.

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Vehicles with 255/40 R21 tires

Configurations in the catalogue recorded with this size. Equipment varies by market and trim.