NASCAR Inside vs Outside Line (Racing Grooves Explained)

NASCAR is a sport that is full of debates, and the argument over whether the inside or outside line is the better of the two grooves is no exception. You may therefore wonder about the issues in the inside vs outside line debate in NASCAR and what racing grooves actually are. 

When comparing inside and outside lines in NASCAR, neither is always better than the other. Some drivers prefer the outside line while others prefer to take the inside racing groove. In some cases, the location of teammates and how a car handles dictates if a driver rides inside or outside. 

Below, we will discuss how NASCAR racing grooves work and why they are so important in a NASCAR race. Finally, we will dive into full detail of why some NASCAR drivers prefer to take the inside track, and why others like the outer line. We will end by exploring the Choose Rule and its importance. 

How NASCAR Racing Grooves Work

You may have heard a NASCAR broadcaster state something in the past regarding drivers finding a groove during a race, but you may not know what that means. The word groove is really a slang term in NASCAR lingo, describing the supposed fastest way around the track for an individual driver

This means there are often different grooves on the track, though narrower tracks may have just one. And depending on their personal preferences, and how their respective car handles, drivers will not always choose the same groove. Weather and track conditions will also affect which groove a driver chooses to take, as both factors will affect cars differently. 

There are often two respective grooves, one being the high groove and the other being the low groove. Some tracks, like Daytona, have more. When a driver chooses the high groove, it means they are driving the car near the SAFER barrier. Drivers opting for the low groove drive closer to the apron (usually the yellow line toward the bottom of the track). 

No Universally Better Groove

One common misconception involving a NASCAR track is that those without extensive knowledge of the sport may believe that there is no universal right or wrong way around the track. One reason for this misconception may stem from a race in track and field, where those who line up on the outside start in front of runners lining up on the inside. 

This is called a staggered start in the world of track and field. However, staggered starts are not necessary in NASCAR even if, theoretically, a driver crosses less ground if they stay in the low groove instead of the high groove. This is because, unlike some track and field events, NASCAR drivers don’t need to stay in a particular lane.

When a driver chooses the low groove, they must either press the brakes more, or during races where braking is not needed, decelerate more. If a driver goes high, they have more track to work with, negating the need for as much braking or decelerating. This allows drivers taking the high groove to drive slightly faster than those going low. 

Racing grooves also form differently, depending on the track’s banking. The steeper the banking, the more potential grooves there are. There could be multiple low grooves or multiple high grooves on tracks like Daytona and Talladega that comprise such steep banking, while flat tracks may just have one high and one low groove. 

Drivers May End Up Outside The Groove

If there is one place drivers don’t want to end up, it is outside the groove. This occurs when a driver opts to go too low, closer to the yellow line, or too high, near the SAFER barrier. Drivers with less experience are more susceptible to driving outside the groove, and in multiple cases, they are increasing the odds of ending up in a wreck or losing track position. 

If a driver finds themselves outside the high groove, they put themselves at risk of hitting the wall. If they drive too close to the yellow line at the low end of the track, it puts them at risk of losing control of their car on the dirty surface. 

Since one of the goals is to remain in a groove, you will always find instances where drivers strategize to keep their position in it, often with the help of teammates and their spotter. Other drivers will try to take their spot in the groove and opposing drivers will try tactics like side drafting to take away the position. 

This means drivers riding in the groove must always pay close attention to what is going on around them, and it is what makes their spotter so important. If a teammate lurks nearby, the drivers can link up and ride the groove together, often providing draft help, which will allow both cars to drive faster, remain in the groove, and either reach or remain at the front. 

You Can See Grooves

When someone first mentions a groove, you may be tempted to think they are nothing more than imaginary lines on a track. But this is not always the case, as a groove is a black line that is most prominent in the turns, and tires mark the grooves’ locations on all tracks. While the groove isn’t there initially, you will see them form as the race progresses. 

How Grooves Form

If you know anything about NASCAR tires, they wear out quite quickly, often intended to last only as long as a full tank of fuel in the early stages of the race. Tire wear causes these grooves to appear, stemming from rubber that comes off the tires building up on the track. 

As this rubber accumulates, it can be a double-edged sword for drivers. In some cases, the added rubber will give them more grip around the track, but in other cases, the tires will lose grip and it can cause handling issues. 


In the latter case, where rubber causes such handling issues by adding ‘marbles’ (chunks of rubber) onto their tires, drivers will take advantage of a caution and swerve during the yellow flag laps. This lets them shed their tires of the marbles that may have transferred from the track surface onto the tires. 


• The racing groove in NASCAR is defined as the fastest way around a given track

• Different drivers may take different racing grooves

• The racing groove can be spotted by a darker line on the track surface, caused by rubber wearing off the cars’ tires

Why Do NASCAR Drivers Take The Inside Track?

On tracks that contain multiple grooves, you will notice drivers will take either the outside line or inside track. Drivers know how well they perform at each respective track, but their car performance also dictates whether the outside line or inside track is best. 

If a driver’s car is slower than the other cars on the track, they will most likely stick to the inside regardless of where they personally perform the best. This allows them to cover less ground. If they drove along the outside line, they are more susceptible to falling behind because of the way their car is driving. 

Suppose the driver’s car, however, is faster than the other cars on the track. This doesn’t necessarily mean they will take the outside line. Instead, those drivers may still opt for the inside track if they prefer to run inside. If a driver passes better on the inside than on the outside, there is little reason for them to take the outside. 

There is also the possibility that a driver’s teammate(s) will take the inside track. To remain fast, a driver may also drop to the inside track to join them, allowing a duo or trio to work their way to the front on the inside. 

Why Do NASCAR Drivers Take The Outside Line?

Every sport contains conventional wisdom, and NASCAR is no different. You will see scores of forum answers that claim the fastest way around the track is to ride high, then stay high until reaching a turn’s apex, before dipping low and staying low before slinging toward the high line again. This may be the case for tracks with just one groove, but it is not always the case

Like drivers who take the inside track, those taking the outside line may do so for similar reasons. If their car is faster, the outside line may be advantageous for them since they can remain close to full throttle through the turns, taking full advantage of any speed differences between the cars. When racing on tracks with steeper banking, this can give a driver even more of an advantage. 

There are outliers, however, just as with drivers taking the inside track. If the car runs better on the outside line, the driver will stay there. However, there may be times where their teammates are riding along on the outside line, which will also give the driver a reason to take the outside instead of the inside to perhaps make use of side drafting. 


• NASCAR drivers will choose to go high or low largely based on their car’s performance

• However, driving style and general preference also play a part

• Both lines can offer advantages to a driver

What Is The Choose Rule In NASCAR?

The Choose Rule in NASCAR allows drivers to choose whether they want to start on the inside or the outside after a race restart. The Choose Rule is a recent concept, having only been part of NASCAR since the 2020 All-Star Race, and it adds another element of strategy to NASCAR restarts.

The 2020 Michigan race was the first race where NASCAR saw the rule in a points-paying event. If you watch a video of a NASCAR restart, you will see an orange V in the middle of the track just beyond the start-finish line. Inside the V, there is a square, which the drivers cannot touch with their tires or drive over. If they do, NASCAR will usually penalize the offending driver(s). 

When the drivers cross the start-finish line during the caution laps, you will see them drive high or low, depending on the factors like their personal preferences, where their teammates are, track conditions, and how their car is driving. 

An Important Rule

Restarts can make or break a NASCAR driver’s race, and there is strategy involved with the Choose Rule in play. In some races, especially at tracks that feature just one groove, you will see many drivers perhaps choose the best line. However, with such a high number of drivers looking to choose the best line, it can cause congestion and ultimately, slower driving. 

This means a few drivers may choose the lesser-desirable line, looking to take advantage of that potential congestion. Choosing the lesser-popular line could also allow drivers running in the middle or back of the pack to move further up the field for the restart. Suppose there are 36 cars on the track and 24 of them choose the outside line. 

Those running closer to the rear can gain valuable track position by choosing the inside line instead, essentially skipping the queue. However, they then need to navigate the less desirable line on the restart, so it’s not always a straightforward advantage, and is quite a gamble. The rule is also not used at all NASCAR tracks, so you won’t see it in action at road courses, Daytona, or Talladega

Final Thoughts

When comparing the inside vs outside line in NASCAR, there are pros and cons for each. While some tracks have just one preferred racing line, many will have favorable inside and outside grooves. Neither groove is universally better than the other, with the choice being affected by many factors.