How does tired tread get “worn” and why do they often wear unevenly, thus the need for rotation?

Question

How does tired tread get “worn” and why do they often wear unevenly, thus the need for rotation?

In: 1

Answer 1

Rubber is softer than concrete. When you constantly have a ton or more of weight on the rubber which is on the concrete, and then apply force to the rubber to spin the tires and make the car move, after enough time the friction wears the rubber down.

The wear unevenly because our roads aren’t perfectly flat and when you run something over, like dummy bumps or rocks, they don’t wear the whole tire, just the points of impact.