How it works

TireFlows

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Result

Diameter

31.56"

Calculated from size marking (math only) — not a fitment guarantee. How it works

Alternate Tire Sizes

Closest diameters (math only · same rim · within 3%)

Tap a size to compare it with your current size

245/70R18-0.19%285/60R18-0.31%255/70R18+1.56%255/65R18-1.62%275/65R18+1.62%275/60R18-1.81%
Width 10.43 ″Rim 18 ″Dia. 31.56 ″6.78 ″Revs/Mile 639.0Circum. 99.2″
Diameter31.56"
Width10.43"
Sidewall6.78"
Circum.99.158"
Revs/Mile639

How results are calculated

Tire dimensions are calculated from the metric size format (width / aspect ratio / rim diameter). Diameter, circumference, and revolutions per mile are derived mathematically — no fitment or vehicle data is used.

The 3% rule is a general reference for acceptable diameter difference, not a guarantee. Always check your vehicle manual or consult a tire professional.

How it works