Why do the fastest bicycles have very thin tires, while the fastest cars have very wide tires?

Question

Can someone explain this?

In: Physics

Answer 1

Turns. Bicycles are low power, and need low wind resistance during forward movement, and have multiple means of dealing with turns (riders can lean, for example, and turns tend to be fairly mild in physics terms). Cars (other than drag cars on a straight line) typically are raced around courses where they need to keep turning — and that means they need enough friction to hold the turn at high speed, which in turn means they need enough width on the pavement, because the friction is proportional to the contact area.