By the way, an increase in pad size is a reduction in pressure per square inch and results in less friction.
That is why skinny tires are better in the winter. Higher pressure will dig down through the snow. Wide tires will ski on top of the snow. Same force (gravity and the mass of the vehicle is constant) yet more friction with less area.
This does not relate to the subject in question as one of the sufaces has seriously deformed therefore giving additional mechanical grip and coefficient of friction. Conversely when traveling in sand the opposite is done and tyres are deflated or wider ones used to give a greater contact area. Both of these examples are not relevant.
I understand pressure it's been part of my working life but there is more than just pressure involved here, unfortunately people are fixating on just this part. There is no denial as vehicles have got heavier and faster that contact (friction) areas have got larger in all areas that need grip - brakes & tyres. This wouldn't have hapened if it wasn't necessary, otherwise we would still have skinny tyres and small linings.
Read these quotes below from Wikipedia:
"Surface roughness and contact area, however, do affect kinetic friction for micro- and nano-scale objects where surface area forces dominate inertial forces."
"The strength of the approximation is its simplicity and versatility – though in general the relationship between normal force and frictional force is not exactly linear (and so the frictional force is not entirely independent of the contact area of the surfaces), the Coulomb approximation is an adequate representation of friction for the analysis of many physical systems."
"Despite being a simplified model of friction, the Coulomb model is useful in many numerical simulation applications such as multibody systems and granular material. Even its most simple expression encapsulates the fundamental effects of sticking and sliding which are required in many applied cases, although specific algorithms have to be designed in order to efficiently numerically integrate mechanical systems with Coulomb friction and bilateral and/or unilateral contact.[25][26][27][28][29] Some quite nonlinear effects, such as the so-called Painlevé paradoxes, may be encountered with Coulomb friction."This has become a sizeable thread, how much more can be said?, Now let's get on to tyres, oil, or which year was the best model.
Regards, Russell