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Nominal Tire Dimensions and Diameter Comparison

Derive sidewall, diameter and circumference from nominal tire width, aspect ratio and rim diameter.

  • Formula & worked example
  • Private in your browser
  • No signup
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A 200 mm tire with 50% sidewalls on a 16-inch rim has 100 mm sidewalls and 606.4 mm nominal diameter.

Sidewall = width × aspect ratio; diameter = rim diameter + 2 × sidewall

Worked example

Enter these known values and leave the other values blank.

Width
200 mm
Profile ratio
50 %
Wheel diameter
16 in
Tire diameter
606 mm
Sidewall height
100 mm
Circumference
1905 mm
Revolutions
525 revs/ km

Assumptions and limitations

  • Nominal code dimensions describe a geometric model. Actual loaded rolling radius, pressure, tread wear and manufacturer dimensions differ.
  • Comparison mode scales indicated speed by the diameter ratio. It does not verify wheel clearance, speedometer calibration, vehicle approval or load/speed ratings.

Common questions

How should I interpret this result?

Nominal code dimensions describe a geometric model. Actual loaded rolling radius, pressure, tread wear and manufacturer dimensions differ.

Can I solve a missing input?

Clear the value you want to find, enter compatible known values, and check the displayed units. Some choices and one-way outputs cannot be solved backward.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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