What size tyres do F1/A1GP use?

[mechsympathy]

Anyone know? Google throws up all sorts of irrelevant stuff.

[absolutely]

Huge! Rolling circumference about 30 inches? Wheel size, 13-15 inches? 12 inches wide?

[mechsympathy]

Trying to find out the diameter. (30" would mean a diameter of approx 18", which doesn't sound too far out.)

[anonymous-user]

F1 2008 Wheel/Tyre

12.4.1 Complete wheel width must lie between 305 and 355mm when fitted to the front of the car and between 365 and 380mm when fitted to the rear.
12.4.2 Complete wheel diameter must not exceed 660mm when fitted with dry-weather tyres or 670mm when fitted with wet-weather tyres.
12.4.3 Complete wheel width and diameter will be measured horizontally at axle height, with the wheel held in a vertical position and when fitted with new tyres inflated to 1.4 bar.
12.4.4 Wheel bead diameter must lie between 328 and 332mm.

[mechsympathy]

26" then. Cheers