Tyre are always a compromise:
- Soft tyres have a firm grip but wear out quickly!
- Harder tyres have less grip but they last longer!
Tyres get very hot at high speeds due to increased downforce
so harder tyres are used on fast circuits so they last a lot longer.
When water covers parts of the track control of the car becomes very difficult.
This is because water forms a layer between the tyre and the track, reducing the normal
(slick) tyres grip.
This effect is termed 'aquaplaning'.
'Wet' tyres with patterns resembling road tyres have to be fitted to the car to remove the water. To increase grip these tyres are normally coated with a softer rubber.
Should the track dry the additional friction forces combined with the absence of a cooling effect from the water will cause such tyres to overheat, lose grip and in extreme cases disintegrate.
In marginal cases experienced drivers in cars with wet tyres can be seen deliberately driving onto wet sections of the track on the straights, to cool the tyres to help them last a few more laps.