How do NASCAR drivers know when to change their tires?

I'm not a nascar driver but have driven racecars on slicks and semi's before. If a tire is over its limit, you will clearly notice it in its driving behaviour. read more

Now remember, NASCAR drivers have little or no information about the status of their car. The Spotter and crew chief know an idea of how much fuel they have and how worn the tires are but sometimes mistakes are made. read more

A fully equipped NASCAR pit crew can change all four tires on their driver’s car in less than 20 seconds! In races like these, speed is always of the essence. A few extra seconds in the pit can mean the difference between first and second place. read more

You may have seen a NASCAR pit stop before. In 12 to 14 seconds, seven people manage to completely refuel the car and change all four tires. This requires incredible hand-eye coordination, but there are a couple of tricks the teams use to make things a little easier. read more