How NASCAR Racing Grooves Work

­As we mentioned on the previous page, NASCAR drivers love the groove because it follows the most efficient path around the track. Since most NASCAR tracks are oval, you might think that any path around them is the same length, but that's not actually true. Think of a track and field race. A long distance track and field race has what is referred to as a staggered start; the runners in the outside lanes start in front of the runners in the inside lanes. The staggered starting positions make up for the extra distance the outside runners will have to cover because the outside lanes are slightly longer than the inside lanes.

That doesn't mean that all racetrack grooves hug the inside of the track. In racing, any time spent slowing down is time lost, so race car drivers don't like to have to slow down as they enter the turns. Hugging the inside of a turn would require a driver to do just that. To avoid having to slow down for a turn, a race car driver will use the whole track -- entering the turn wide, but then cutting in close to the inside edge at the last possible second. While this strategy may lead to the car covering a slightly longer distance, the car can cover that distance much faster than it could cover the shorter, inside distance if the driver had to apply the brakes for each turn. Often, a NASCAR race car on an oval track can remain at or near full throttle for the entire lap.

What makes the groove depends on how the individual track is constructed. NASCAR tracks have banked curves. That means the track surface tilts inward, toward the center of the track; the banking runs perpendicular to the direction the cars are moving. Banking the curves allows the cars to really attack them without having to slow down. In fact, going too slowly on a steep-banked curve can spell trouble. The banking allows the cars to slingshot around the curve. Where the groove is located, as well as how many grooves there are -- remember, some tracks have more than one -- depends on how steep the particular curve is banked.

On the next page, find out what happens when a driver ends up outside of the groove.

Driving outside the groove means that the car isn't following the most efficient path around the track. That means that instead of being in the groove, the car is either too close to the outer wall of a turn or too close the apron, a term for where the flat infield meets a banked turn on a track.

As you can imagine, both situations can be disastrous for drivers -- for a variety of reasons. Being in the groove isn't only about maintaining speed and winning the race. Being in the groove also lessens the chance of an accident. Near the wall, there's always the chance of being pushed into the wall, or slamming straight into it when the car is coming out of the turn. Driving on the apron is no better. Staying in the groove and off the track's apron helps the driver maintain control. While everyday drivers may have driven onto the shoulder of a turn without disastrous results, at the speeds NASCAR race cars travel, the results can be catastrophic. One of the most famous examples of this is the on-track death of racing legend Dale Earnhardt at the 2001 Daytona 500. Earnhardt was the middle of three cars on the final lap of the race -- Daytona International Speedway has three grooves -- when his left rear fender was nudged by the car on the inside groove. That caused Earnhardt's car to hit the apron and lose control, sending it back up the banked track and into the wall, along with another car.

­In terms of racing strategy, because the groove is the fastest and safest place to be, drivers try to get into it and keep other drivers out of it. To do so, drivers rely on teammates on the track for drafting and help with passing as well as other crew members who act as race spotters to let them know what the other drivers are up to. Even when they're in the groove, NASCAR drivers must constantly monitor shifting racing conditions, including the ever-changing positions of the competition, to maximize their advantage.

­Driver positions aren't the only constantly changing factor during a race. Read the next page to find out how the groove can change during a race, too.

­In racing, staying in the groove means that a car can stay at or near its top speed for as long as possible. The driver won't have to slow down or waste time (and distance) trying to get into the optimal position. That may sound rather simple, but the groove can change as the race goes on.

As we mentioned earlier in this article, you can typically see the groove (or grooves) on a track because of the build up of rubber from the tires. NASCAR race cars use racing slicks. Racing slicks are a kind of tire that doesn't have ridges or grooves like a normal tire does. Instead, racing slicks are smooth on the surface that contacts the track. The racing slicks are made out of a soft rubber that gets sticky as it heats up. That sticky rubber helps the car adhere to the track; however, the tires are so soft and sticky that some of the rubber sticks to the track itself. That's what creates the black line that makes the groove visible.

Depending on the race-day weather conditions, that extra rubber on the track can either benefit or harm the drivers racing in the groove. If the race is held on a hot day and the track surface is warm, the extra rubber will quickly heat up and become sticky, giving any car in the groove extra traction -- a definite plus. Conversely, if the track is cold, that extra rubber will harden, making the groove a slippery place to be. If the groove is slippery, drivers try to avoid it by taking the next most efficient route around the track.

­It's easy to see how changing weather conditions -- and changing groove conditions -- can make a driver change his race day strategy. But what happens when there's more than one racing groove to choose from? Read the next page to find out how the strategy changes when a track has two or more racing grooves.

­By now, you know that some tracks on the NASCAR circuit have multiple grooves. Whether or not a track has more than one groove depends on how wide the turns are. When a track has more than one groove, that means the turns are a great place for passing. If a car can get around another car on a turn, it can then cut in front of the car it just passed to take the lead position when the track straightens out. While using multiple grooves for passing on the turns makes for exciting races, it can also be very dangerous. Turns are always pressure-filled points on any NASCAR track. A little bump or nudge from another car in a turn can end a driver's race day in a split-second.

When a NASCAR track has two grooves, the one on the outside is referred to as the upper groove, and the one on the inside is called the lower groove. When a track has three grooves, the upper and lower grooves keep their names and the middle groove is called -- you guessed it -- the middle groove.

When it comes to race strategy, the conventional wisdom is for drivers to take and hold the inside groove. That means they have a shorter distance to cover. It also means that most passing takes place in either the middle or upper grooves. If a track has only a single groove, cars will battle for position on the long straight sections of the track and fall into line for the turns. Each track on the NASCAR circuit offers its own, unique style of racing. NASCAR aficionados may debate over which tracks offer the best grooves for racing excitement; but now that you know the basics of NASCAR racing grooves, you can join in the debate, too.

Groove on over to the next page for more information about NASCAR, racing and other related topics.