It is nitrogen.
The company that makes the best car tires is mainly a matter of opinion except there are a few brands of tires that are better: What company makes the best car tires
Slicks.
nitrogen
The tires of the car
The best tires for a small car would be the ones that the car manufacturer recommends you use on the car. If you keep good tires on your car and check them every now and then you will get better gas mileage.
A couple of years ago FIA changed the rule that stated a car can change the pneumathics (tires) when in pit stop during the race. Now they can only use the set of tires that they start the race with.
Race car tires are super sticky. And when I say sticky I mean like GOO. A pebble pushed onto the smooth tread will STICK there. These tires are not legal for street use.
Hankook are excellent tires. Next time you go to a car race track, or drag strip, look around and see how many tires are Hankook.
It costs approximate $200,000 (minimum) to race a NASCAR Sprint Cup car in ONE RACE.
pulls tires off road, reducing traction.
There are many good wearing brands of new car tires. For example, tires from the company Michelin are really good tires for cars worldwide and in America.