We see it at the races, and when we watch a race on TV or a movie.. Just before the start of the race, the cars weave back and forth, back and forth in a tight  "Z"  pattern down the track. The purpose is the heat up the tires so they grip the pavement.

This happens because as they weave back an forth in the tight pattern, the surface of the tire scrubs the pavement.. friction, and friction makes heat... so, warm tires.

Not as often, but on occasion, at a motorcycle race, we see some one doing the same thing, weaving back and forth. We think.. he's warming up his tires for better traction. So, why aren't they all doing it?  Well, pros know better!

Think about it... a motorcycle tire is rounded, the tread is not flat on the road as it is on our four wheel cousins. When we turn our bikes, we lean in the direction we want to go, or counter steer to lean the bike. The bike tire runs on the side. That's why they have tread almost all the way around. So what happens the surface of the tire that meets the road keeps changing and parts of the tire are in the air, COOLING IT DOWN !