The first classical law of friction states: “The size of the contact surface does not influence the friction”. Why, then, are tires for the Formula 1 racing cars so wide?

According to the “FIA Technical Commission”, the organisation that decides on the technical rules for Formula 1, the front tires should not be wider than 355 mm (i.e. 14 inches) and the rear tires no wider than 380 mm.

The classical friction laws apply to materials that undergo mainly plastic deformation in the asperity summits. This in not the case for polymers (and elastomers). Polymers display a lower friction coefficient at higher nominal contact pressure. A high friction force can consequently only be achieved with a large surface area.

Other advantages of a wide surface are that the wear is distributed over a larger area, heat development per unit of surface is lower and the result is a larger heat-radiating surface.

A racing tire performs optimally at an operation temperature of 100°C-110°C. During racing, the tire temperature is measured constantly and the data passed on to the driver. If the F1-car is getting ready for the race, the tires’ temperature is raised with tire heaters. A sort of electric blanket is used to pre-heat the tires to 80°C. Why is the tire temperature so important and what would happen if the temperature would become too high?