NASCAR tires look completely bald, but that's not because they are worn out. It is by design. On a dry track, tires can generate more traction if more of their sticky rubber is in contact with the ground. Putting a tread pattern on the tire helps in wet weather, but in dry weather it is better to have the whole tire touching the ground. That's why NASCAR races stop whenever the track is wet.
Link: http://entertainment.howstuffworks.com/nascar5.htm On the road courses at Sonoma and Watkins Glen, each team has at least one set of rain tires. You wouldn't kill yourself if you ran in the rain on a road course (you probably would if you did it on an oval), so the protocol for rain is to throw the yellow, get everyone in and change to rain tires. I'm not sure if they ever have done it, but they can.
F1 teams use Nitrogen to fill the tires because of its low dilatation compared to air, a small dilatation in a F1 tire will result in unbalancing the car.
nitrogen
The F1 tires used in Formula 1 racing are approximately 305mm wide.
suspension.
Some are directional like the eagle F1, however most are not directional.
They use air filled tyres, which is why you see them getting punctures.
F1 tyres are filled with Nitrogen since it is a more stable gas than air
Soft tires are better because they are smooth on the track which gives them more speed.
Please be careful with that f1 key.
F1 cars swerve during races to warm up their tires and maintain optimal grip on the track, which helps improve performance and handling.
All teams have access to a live weather radar and hence can predict when rain is approaching the circuit.
so that less friction is caused, and to improve speed