is friction depend upon area or not when both the surface are extremly smooth??

Force of friction that two bodies experience when rubbing or sliding against each other depends on both the area as wel. as the smoothness of the surfaces. The latter is dependant on the coefficient of friction which is different for different materials depending upon the smoothness, adhesion, cohesion of the surface of the object. Along with, the force of friction os dependent upon the surface area in contactwhich is in direct proportion with force of friction.

This is the reason why bike tyres with broader bases and more grooves have a better grip on the roads than the narrow ones as they have more area of contact with the road.The coefficient of friction in this example plays role as their are many materials used for making the tyres, some of which are meant for roads, mountaineous terrains or even bumpy watery roads. During rainy seasons, one can observe that surface area of the road with the same tyre remains same, still vehicles skid off the road the reason for which is coefficient of friction getting changed.