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Wheel Offset

Free Wheel Offset calculator with clear step-by-step results.

About Wheel Offset

Offset is measured from the mounting face to the wheel's centreline, so changing both width and offset moves the inner and outer edges independently. The inner figure is what determines strut and suspension clearance; the outer figure determines arch clearance and whether the tyre protrudes.

Formulas

Inner edge position

Inner = wheel width / 2 + offset

Outer edge position

Outer = wheel width / 2 - offset

Worked example

With the default values below, Wheel Offset returns Outward movement of the outer edge of 22.70. Change any input above and every figure here is recalculated in your browser.

Inputs used

Current wheel offsetaccepts -80–100 mm
45 mm
New wheel offsetaccepts -80–100 mm
35 mm
Current wheel widthaccepts 4–16 in
8 in
New wheel widthaccepts 4–16 in
9 in

Results

Outward movement of the outer edge
22.70 mm
Inward movement toward suspension
2.70 mm
Track change per side
22.70 mm
Total track change
45.40 mm

Step by step

  1. 1Values used
  2. 2Inner edge position
  3. 3Outer edge position
  4. 4Outward movement of the outer edge= 22.70 mm
  5. 5Inward movement toward suspension= 2.70 mm
  6. 6Track change per side= 22.70 mm
  7. 7Total track change= 45.40 mm

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Wheel and tyre fitment affects steering geometry, bearing loads and tyre containment within the bodywork. Non-compliant fitment can breach construction and use regulations and invalidate insurance.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Wheel and tyre fitment affects steering geometry, bearing loads and tyre containment within the bodywork. Non-compliant fitment can breach construction and use regulations and invalidate insurance.

Frequently Asked Questions

Does a lower offset always push the wheel out?

For the same width, yes - reducing offset by 10 mm moves the wheel 10 mm outward. But widening the wheel moves both edges outward by half the width increase as well.

What clearance do I need on the inside?

At least 5 mm static to the strut and more at full lock and full suspension travel. Inner clearance is where most fitment failures actually occur.

Related Calculators

Wheel Offset – Calculate Outward movement of the outer edge