The Operating Window
A racing tyre only works properly inside a temperature range. Below it the compound is too stiff to generate the mechanical and chemical adhesion it depends on, so the tyre feels wooden and the driver cannot lean on it. Above it the surface becomes greasy and grip falls away. Between the two lies a window in which the tyre delivers what it was designed to deliver.
This window is why tyre performance is not a straight line from new to worn. A set can be slow because it is too cold, quick once it comes in, and slow again once it overheats. It also explains why the same compound behaves differently for two drivers in the same car: one who loads the front axle aggressively on entry pushes the front tyres up through the window faster and can overheat them while the rears are still short of temperature. A tyre that will not reach its window in cool conditions is not a strategic option regardless of its theoretical lap time.
