Why do F1 teams heat the tyres?

Warm tyresToday's F1 cars are running 18-inch wheels (up from 13 inches in recent years) with the widths unchanged - 305mm... There's more... have more gripGrip is the magic that holds the car on the road as it accelerates, turns and brakes at extreme levels.... There's more... so heating them before they go on the car means that they are in the window immediately.

In sports categories where tyre warmersTyre warmers, or tyre blankets, are used to pre-heat the tyre before it is put onto the car. Tyres need... There's more... are not used, the driverOK, so we all know what the driver is, right. I've always liked the description that F1 drivers are like... There's more... needs to warm the tyres by spinning them or weaving on the track to create heat through friction. 

Tyre warmers, or tyre blanketsTyre blankets, or tyre warmers, are used to pre-heat the tyre before it is put onto the car. Tyres need... There's more..., are essentially electric blankets that heats the tyres to 100C (212F).

They have been a major topic of discussion and are likely to be phased out to reduce high energy consumption, and costs,  placing the onus of bringing the tyres into the operating window back onto the driver.