Achieving maximum traction while in motion is something quite different. As the tire grips, it also wears. What “wears out” are the various chemicals, oils, waxes, and pigments that bind the rubber together. Abrasion and heat “cook” these compounds off. You’ve noticed the bluish-purple color of a tire that’s been subjected to hard cornering? That’s called “blooming,” and it’s caused by residue from the chemicals that have been leached out of the tire by heat. It takes very little abrasion to wear the bloom off—maybe a lap.