Glossary
Tyre Temperature Spread: How to Read a Pyrometer and Tune Setup
Tyre temperature spread is the difference in surface or core temperature across the inner, middle and outer thirds of the tread, taken with a probe pyrometer immediately after a run. The pattern tells you whether the contact patch is loaded evenly: camber sets the inner-to-outer gradient and pressure sets whether the centre is hotter or cooler than the edges. A healthy race tyre shows the inner edge 5–15°C hotter than the outer with the centre in between.
| Pattern (I / M / O) | Meaning | Adjustment |
|---|---|---|
| 95 / 88 / 80 | Ideal gradient | None |
| 105 / 88 / 75 | Too much negative camber | Reduce camber 0.3–0.5° |
| 80 / 86 / 95 | Not enough negative camber | Add camber |
| 85 / 98 / 85 | Pressure too high | Lower by 1–2 psi |
| 95 / 82 / 94 | Pressure too low | Raise by 1–2 psi |
| Front avg 20°C above rear | Front working harder (understeer) | Shift balance rearward |
Taking good measurements
Use a needle probe pyrometer, not an infrared gun, because the surface cools within seconds and infrared reads the surface only. Probe about 3 mm into the rubber at three points across each tyre, starting with the tyre that worked hardest on the in-lap. Always use the same order and have the driver do a consistent in-lap: a slow cool-down lap erases the information.
Using the data
Compare left versus right on the same axle to check static camber and pressure, and front versus rear to check balance. Trends across a session are more useful than one reading. Setup Genius stores per-corner inner, middle and outer temperatures against each setup so the pattern is visible when you look back at a previous event.
Frequently asked questions
Why is my outer edge hottest even with lots of negative camber?
Possibly the car rolls so much that the camber gain is used up, or the tyre pressure is too low and the shoulder is folding under. Check roll stiffness and pressure before adding more camber.
What is the ideal absolute temperature?
It depends on the compound; the manufacturer quotes a working window, often 80–110°C for slicks. Spread matters more than the absolute number for setup.
Can I use tyre temperatures on a dirt track?
Yes, but the pattern is different because the tyre slides constantly. Dirt racers mainly use temperatures to compare left and right rear and to judge stagger.
Related
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