Tire size comparison

Compare two labeled sizes by theoretical diameter, circumference and revolutions per mile.

Reference size

Comparison size

Diameter differenceEnter values to calculate

A geometric comparison only

The percentage compares theoretical overall diameters. A positive result means the comparison label produces a larger diameter in the formula.

A percentage is not an approval

Fitment also depends on wheel width and offset, clearance, load and speed ratings, manufacturer tolerances and vehicle systems.

More tools

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Calculate theoretical diameter and circumference.

Speedometer error

Estimate geometric speed change from tire diameter.

RPM & road speed

Relate speed and RPM through tire and gear ratios.

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Calculate oil from a manufacturer-specified ratio.

Wheel offset

Compare inner clearance and outer wheel position.

Compression ratio

Calculate static ratio from cylinder and clearance geometry.

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Calculate total displacement from bore, stroke and cylinders.

Power to weight

Compare horsepower and vehicle weight in common units.

Sprocket ratio

Find chain-drive ratio and driven sprocket RPM.

Injector size

Estimate per-cylinder fuel flow from explicit assumptions.