Talk the talk

Even for those fans who devote every Sunday to Jesus and NASCAR (not necessarily in that order), racing lingo can be a tad complicated. Loose, tight, drag, stroking, groove--it all sounds a bit like a bad one-night stand. And Robert Duvall's bewildering explanation in Days of Thunder does nothing but confuse the matter. Fortunately, with the help of Brendan Gaughan's crew chief, Shane Wilson, we can set the record straight.

Downforce: Air traveling over the surface of a race car creates downforce, which helps the car grip the track.

Drag: Drag is the resisting force exerted on an object passing through air at high speeds. Downforce and drag are directly proportional, meaning that the more downforce applied to a car, the more drag the car must overcome.

Dirty air: Depending on who you talk to, dirty air can mean one of two things. According to Wilson, dirty air is the turbulent wind created by the lead car that causes trailing cars to lose downforce (this is also known as aero push). Others say dirty air is simply the air used and discarded by the lead car.

Groove: The quickest path around a racetrack. The high groove takes the car up near the outside wall; the low groove brings it down around the apron.

Loose (or oversteer): When a car has more bite in the front than the back, it is said to be loose, which essentially means that its back side is sliding around like butter on a hot frying pan (particularly in the corners).

Tight (or understeer): If a car's tight, it means the rear end is sticking to the track, making it difficult for the driver to steer. A car that's too tight will push straight through a turn and up into the wall.

Stroking: A driver who's stroking is hanging back in the pack trying to preserve his equipment. At certain tracks--Daytona and Talladega, in particular--it can behoove a racer to stroke. At 1.5-mile ovals like the Las Vegas Motor Speedway, stroking can leave a fast car out of the top 10.

Wedge: When it comes to racing, wedge is a little bit like Nietzschean philosophy--people love to talk about it, but few seem to know exactly how it works. Basically, wedge expresses the difference in weight between the front and rear corners of a car. If a car's loose, you want to take wedge out (i.e., transfer weight to the rear). If it's tight, you want to add a round of wedge (transfer weight to the front).--Newt Briggs