Hot-to-Cold Tyre Pressure Calculator

When to use it

• Compare how a change in target hot pressure affects required cold pressure before committing to parts, setup, or strategy changes.
• Check a workshop, dyno, simulator, or trackside spreadsheet result using a transparent formula: Hot absolute pressure × cold/hot temperature ratio.
• Use the result before changing wheels, tyres, brake hardware, or pressure targets. Track temperature, tyre construction, pad compound, surface grip, aero load, and driver technique can all change the real outcome.

How to use it

1. Enter target hot pressure in psi; the default value shown is 34 psi.
2. Enter hot temperature in °C; the default value shown is 80 °C.
3. Enter cold temperature in °C; the default value shown is 20 °C.

How to read the result

Required cold pressure is shown in psi. Use the number as a calculated reference point, then compare it with measured data from the car, the part supplier, or the race environment. A mathematically clean answer can still be unsuitable if the inputs are estimated, rounded, measured under different conditions, or outside the normal range for the vehicle.

Assumptions and checks

• The calculator applies the displayed formula directly and assumes the entered target hot pressure, hot temperature, and cold temperature are valid for the vehicle and conditions being considered.
• Changing target hot pressure and hot temperature together can move the answer in ways that are easy to miss, so make related setup changes deliberately.
• Measure clearances on the actual vehicle because wheel and tyre shapes vary between manufacturers.
• Check brake calculations against pad data, disc radius, hydraulic layout, and balance-bar setup.
• Recheck tyre pressures hot and cold at the circuit rather than relying only on a static estimate.