What the calculations can tell you

What is included

The tire tools derive nominal sidewall height, rim diameter, overall diameter, circumference and revolution counts from a metric size. Comparisons add signed differences and a theoretical circumference-ratio speed table. The wheel tool compares rim-width reference positions from a fixed mounting face.

What is not measured

TireSpan does not measure a tire, wheel, vehicle or road speed. It does not know a tire model’s real dimensions, loaded shape, wear, inflation or rolling circumference. The directory’s product sources confirm markings; they do not turn the calculated output into a manufacturer measurement.

What is not a fitment check

The tools do not verify load or speed ratings, approved wheel widths, bolt pattern, hub bore, brake clearance, suspension travel, body clearance or vehicle-specific requirements. No percentage band or same-size result is an automatic approval.

What the service does not offer

There is no VIN, license-plate or vehicle-model lookup, stock listing, tire sale or appointment booking. No AI service evaluates your inputs. Calculations run locally in the browser after the page and its assets load.

Use the right source for the next question

Read the applicable vehicle information and the exact tire or wheel specification for a replacement decision. A competent physical assessment may be needed where clearances or changes to the assembly are involved. The downloaded report is a record of the nominal comparison, with its assumptions visible.

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