MachineCalcs

Tire Contact Patch Calculator

Estimate tire normal load, contact patch area and patch length from corner load, load transfer, aero load and inflation pressure.

Calculator

Static scale load at this tire.

kg

Signed load added to this tire. Use negative if load is removed.

kg

Downforce at this tire as mass equivalent.

kg

Cold or hot inflation pressure. Gauge pressure is a practical approximation for patch area.

bar

Approximate loaded tread width in contact with the road.

mm

Results

Default result
Edit inputs
Normal load
390kg
Pass

Also computed

Normal force3,825N

859.8 lbf

Contact areaPass17,380mm²

Patch length79.02mm

Method notes 2 notes
  • Contact patch area is approximated as normal force divided by inflation pressure. Tire carcass stiffness and tread shape change the real footprint.
  • Use this as a load and pressure screen, not as a tire grip model.

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How to use this calculator

  1. Enter static corner load. Use scale weight at the tire.
  2. Add transfer and aero load. Use signed transfer and downforce as load equivalents.
  3. Enter tire pressure and tread width. Use the pressure and effective contact width being evaluated.
  4. Read patch area. Review normal load, area and approximate patch length.

How it works

The calculator combines static load, transfer and aero load, then divides the resulting normal force by inflation pressure: area = normal force / tire pressure.

Feed it with weight transfer or roll-center load transfer results when checking cornering or braking load cases.

Worked example

Verified against the live calculator

A tire carrying 390 kg at about 32 psi has a first-pass contact patch near 17,400 mm2, or roughly 79 mm long with a 220 mm effective tread width.

Frequently asked questions

How do you estimate tire contact patch area?

A first-pass estimate divides normal force by tire inflation pressure.

Is contact patch area exactly load divided by pressure?

No. Tire construction, carcass stiffness, tread shape and camber change the real footprint.

What is load transfer in this calculator?

It is signed load added to or removed from this tire during braking, acceleration or cornering.

Should I use cold or hot tire pressure?

Use the pressure state you are trying to evaluate. Hot pressure is often more relevant for track loading.

Method & assumptions

  • Approximates area from load divided by gauge pressure.
  • Does not model tire stiffness, camber thrust, pressure distribution, compound or load sensitivity.
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