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EV & CarsGenerated accuracy model review: 2026-05-06

Tire Size Comparison Calculator accuracy and testing

This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.

Formula source

  • Tire diameter = rim diameter + 2 x width x aspect ratio / 25.4. Speedometer adjustment follows the diameter ratio.

Test cases

Default input regression check

Generated from the checked-in default inputs and calculate function.

Inputs

  • Original Width: 225 mm
  • Original Aspect Ratio: 55%
  • Original Wheel Diameter: 18 in
  • New Width: 235 mm
  • New Aspect Ratio: 60%
  • New Wheel Diameter: 18 in
  • Indicated Speed: 60 mph

Expected outputs

  • Diameter Difference: 4.90%
  • Original Diameter: 27.74 in
  • New Diameter: 29.1 in
  • Estimated True Speed: 62.94 mph
  • Ride Height Change: 0.68 in

Known limitations

  • This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
  • Use the result as a planning estimate unless the calculator page states a stricter purpose.

Assumptions

  • All prices, fees, rates, and vehicle assumptions are user-entered.
  • Calculations run locally in your browser and are not stored by Calwarden.
  • This is planning math, not financial, tax, insurance, legal, or mechanical advice.

Unit handling

  • Original Width accepts values in mm.
  • Original Aspect Ratio accepts values in %.
  • Original Wheel Diameter accepts values in in.
  • New Width accepts values in mm.
  • New Aspect Ratio accepts values in %.
  • New Wheel Diameter accepts values in in.
  • Indicated Speed accepts values in mph.
  • Diameter Difference is displayed as a percentage.
  • Original Diameter is displayed in in.
  • New Diameter is displayed in in.
  • Estimated True Speed is displayed in mph.
  • Ride Height Change is displayed in in.

Rounding rules

  • Number displays use up to 2 decimal places in the calculator UI.
  • Percent outputs are displayed with two decimal places.
  • Input precision follows configured step values where provided.

Version history

1.0.0 - 2026-05-06

Generated accuracy and testing page from the current tire-size-comparison-calculator calculator definition.

Change log

2026-05-06

Published default regression test documentation and metadata fallbacks for Tire Size Comparison Calculator.

Calculator transparency

Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.

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