Pro Engineer/Tyre heat
Why your tyres overheat — and what the three numbers across the tread mean
One temperature per tyre tells you almost nothing. Three tell you what to change.
A tyre that reads 95 °C can be perfect, over-inflated or rolling onto its shoulder, and the single number every dashboard shows you cannot tell those apart. Assetto Corsa publishes the temperature at the inner, middle and outer third of the tread, and the difference between them is the answer.
THE PATTERN YOU WANT
Rubber does not simply rub against the road. It deforms into the pores of the asphalt and springs back, and that deformation is where the heat comes from — hysteresis, not friction in the school sense. Where on the tread that happens is decided by camber, pressure and how the car is loaded, and each of the three leaves a different fingerprint.
Inside | Middle | Outside 95 °C | 90 °C | 82 °C <-- what a well set-up tyre looks like
The inside is hottest on purpose. A race car runs negative camber, so the tyre stands on its inner edge on the straight and rolls flat onto the whole tread as the car loads up in the corner. If the inside is not the hottest, the tyre is not arriving at the corner the way it was meant to.
THE THREE PATTERNS THAT MEAN SOMETHING IS WRONG
Middle hotter than inside and outside
Over-inflation. The tyre has ballooned: too much pressure has pushed the centre of the tread into the road and lifted the shoulders off it. You are driving on a strip down the middle of a tyre you paid for all of. Take pressure out.
Outside hotter than inside
Not enough negative camber. The tyre is rolling over onto its outer shoulder in the corner, which is both slower and how a tyre gets destroyed in a stint. Add negative camber until the inside comes back to being the hottest of the three.
All three climbing and never settling
That is not a camber or pressure fault. A tyre that keeps heating through a stint is being asked to do too much for too long: too much sliding, too much load transfer, or a compound that is wrong for the track temperature. Look at the slip figure at the same corner on successive laps — if it is rising, the tyre is giving up rather than the setup being wrong.
PRESSURE IS A TEMPERATURE PROBLEM
Cold pressures are a means, not an end. What matters is the pressure when the tyre is hot and working, and every car states its own window in its own files — which is why a number copied from somebody else's setup, on a different track on a different day, is a guess. Pro Engineer reads the figure the car itself states rather than a class average, because a GT3 and a formula car do not share a window and a car with an unusual one is exactly the car somebody needs telling about.
Competizione publishes no temperatures across the tread. The inner/middle/outer reading above is Assetto Corsa only — and rather than showing you three copies of one number, the camber and wear advice is simply withheld there. A verdict that rests on a measurement the game does not publish is a verdict about nothing.
YOU DO NOT HAVE TO READ THE MATRIX
All of the above is arithmetic, and arithmetic is what a program is for. Pro Engineer watches the three zones on all four tyres sixty times a second and says which of these it is, in a sentence, while you drive — with the measurement it read, the mechanism behind it, and what to look at next run to know whether the change worked.
It is free, there is no account and nothing is uploaded. Download it · the full chapter on tyre heat