Air Compressor
An air compressor powers tools in the pit area

At the other end of that air hose is a compressor that powers the air gun.

Todd Warshaw/­Getty Images for NASCAR

­An air compressor powers most NASCAR crew tools, but the term "air compressor" is a little bit of a misnomer. NASCAR air compressors aren't filled with air, they're filled with nitrogen. But the compressor still works in much the same way the air compressors at your local repair shop do. The compressor pressurizes the gas inside it, so when the gas is released, it comes out with a great deal of force. That force is used to power tools like the air gun.

Why do NASCAR teams use nitrogen in their air compressors? Nitrogen is more consistent than air -- it doesn't react as dramatically to changes in temperature or humidity. With nitrogen in their air compressors, NASCAR crews can be assured that the equipment won't malfunction because it's a particularly hot or cold race day.

­Before the air compressor or the air gun can combine efforts to remove the tires, the car has to be raised -- and quickly, too. On the next page, find out how NASCAR crew members get the car up in the air so fast.