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human
ELI5: If dry friction does not depend on surface area, why do racing cars have wide tires?
gpt
>If dry friction does not depend on surface area, why do racing cars have wide tires?

You are correct that static friction depends only on the coefficients of friction of the two surfaces, and the normal force between them.

But if the contact patch between the tire and the road is very small, slippage (which there will be some of with aggressive racing) can result in overheating that small contact patch and damaging/melting part of the tire, rather than the resultant heat being dissipated through a larger tire.

Further, softer tires have increased friction, which means better traction and faster acceleration.  But the force on the tire stays the same regardless of surface area, which means that smaller tires have the same force concentrated onto a small contact patch, which can shred the softer material.  A larger tire means that the force is dissipated over a larger are, so the force / cm^2 is lower, and you can safely use softer tires with higher coefficients of friction.