Circle of forces

A tire can generate horizontal force where it meets the road surface by the mechanism of slip.

That force is represented in the diagram by the vector F. Note that in this example, F is perpendicular to the plane of the tire.

That is because the tire is rolling freely, with no torque applied to it by the vehicle's brakes or drive train.

In the example, the tire is generating a component of force in the x direction (Fx) which, when transferred to the vehicle's chassis via the suspension system in combination with similar forces from the other tires, will cause the vehicle to turn to the right.

Drag of this kind is an unavoidable consequence of the mechanism of slip, by which the tire generates lateral force.