Here are foam DONUTS for your F1 car. Sized for F-1 Cars like the Tamiya F103 or the 3 Racing F109.
Fronts are 2.40 inches in diameter & 1.28 inches wide. (61mm x 31mm). Inside diameter of the donut is 1.2 inches (30.3mm)Compound is a Medium Firm hardness with a shore rating of 42. These donuts are suitable for outdoor asphalt as well as indoor carpet racing.
Mount with rubber contact cement or double sided tape.