Why might the law of friction not apply to tires/wheels?

I understand the law of friction, but I just can't get why it might be different for wheels. Is it because the wheels are turning so the surface touches the ground only for a tiny amount of time?Why might the law of friction not apply to tires/wheels?
The motion of a wheel is propelled by static friction and only kinetic friction can slow down an object. Just so everyone knows, "rolling friction" is static friction for a wheel.
There might be no friction, because the surface of the tire is not moving, or trying to move, relative to the ground, even though the vehicle is moving. The velocity of the vehicle is v, the velocity of the center of the wheel is v, the velocity of the top of the wheel is 2v, and the velocity of the bottom of the wheel is ZERO.



It's just the same as a box just sitting there on the floor. The potential static friction is uN, but the actual friction force is zero, because the box is neither moving nor "attempting" to move.



On the other hand, if the car is accelerating, the bottom edge wheel is "attempting" to move backwards against the ground. Static friction force prevents that from happening, while at the same time accelerating the car, unless you exceed the limit of static friction. Then the wheel spins (peeling out) and kinetic friction is involved.



If the car is braking, the wheel is "attempting" to slow down, which would make the bottom not go "backwards" fast enough, so the bottom is "attempting" to move forward with respect to the ground. The result is a backwards static friction force. If the limit of static friction is exceeded, the car would "skid", in which kinetic friction is involved.



When cornering, static friction (hopefully) is involved in a direction parallel to the axis of the wheel. In that direction it doesn't affect the rotation of the wheel.



Whenever the wheel is turning, "rolling friction" is involved. That's actually a catch-all term that includes the effects of kinetic friction in the axle bearing and non-elastic deformation of the tire.Why might the law of friction not apply to tires/wheels?
Who told you it was any different for tires/wheels?

Many of the concepts that apply to a box on a ramp also apply to a wheel on the road. You just need to think about it more.
Its not different. First, convince yourself that friction is a force that tries to stop relative slipping. When you walk, what you actually do is push the ground backwards. When you start pushing ground backwards by the use of friction, the friction is applied on you by the ground as a result of Newton's 3rd law (Action-Reaction pair). This makes your one feet stationary and fixed which gives you the opportunity to lift your other leg and move it forwards without going back.



Similarly, wheels push ground backwards, they get pushed forwards and they move forwards.Why might the law of friction not apply to tires/wheels?
The frictional force is what allow th wheel to rotate. The forward force of engine is compensated by frictional force of tyre(This is true till car is not skiding).



The rotation of wheel is torque created by frictional force. The direction of rotation is toward the frictional force.



This is the reason a good tyre is which has more treads, means can provide more friction.



So which law of friction is not applicable here?
Actually friction applies for tires and wheels just as it applies for any other object. The force is different because:



In an object like a box, the whole bottom rubs with the ground when u push it forward. That creates friction and slows it down.



In a wheel, the wheel turns (say) clockwise, and then the bottom of the wheel will be moving back relative to the center. Friction doesn't let it slide back on the ground and thus creates a frictional force in the forward direction. (If this force isn't there, the wheel would just slip) The Friction in the forward direction keeps the point of contact stationary but the rest of the wheel moves forward. Then that point leaves the ground and a point a bit in front takes it's place. This is how a wheel works.



Ancient science...
Rolling friction deals with molecular adhesion.
No, it's different because you're not talking about smooth surfaces. The tire deforms, and "keys" to the irregularities of the road, giving it far more grip than the law of friction would suggest.
there's static friction and sliding friction, same as for sliding objects.

there is also rolling friction, which is related to energy absorbed in the tire due to deformation.

Steel wheels like in a train have much lower rolling friction than rubber tires, which is why trains are more efficient than trucks



There is not a significant gripping effect of tire treads on tarmac. A tire is not a gearwheel. The static friction is around 0.7 or so for regular tires, comparable to smooth rubber on smooth concrete.

Metal cleats on earthmovers might be different.