Nascar: Terminology of the Sport 2

Have you ever been watching a race and heard the commentator say they are taking some wedge out or going up on the track bar and wondered what they were talking about? Well I will explain these and a few other aspects of the set up of a NASCAR race car.

First of all the crew chief keeps detailed notes from each track they race so when the car is built and set up in the shop the adjustability can be built in. Setting the camber or lean of each tire is something that can not be adjusted easily during the race. If camber must be changed after a race starts you will lose laps and the race. The easiest way to explain camber is if the tires were set to zero camber or straight up and down they would make perfect contact with the pavement on the straight-aways but in the corners the tire would ride on the edges of the tires. Since the corners are where the most grip is needed then you would want more contact in the corners so you set your camber to provide the biggest contact patch there. NASCAR does regulate the maximum amount of camber that can be used; this is for safety as too much camber will wear a tire quickly causing blowouts.

There are quite a few things that can cause a tire to blowout; such as tire pressure being to high, too low can cause the separation of the tire from the rim, front shocks or springs allowing to much travel rubbing the tires and excessive heat in the brakes will also cause tire failure. Blowouts or flats are among the most common reasons a race is lost.

I guess I have to get back to simple so let’s pretend that I have already covered; shocks, springs, chassis geometry and fender flare.

So what is a track bar? It is a bar that changes the rear end geometry of the car. It is mounted across the rear bell housing of the car or in simpler terms the rear axle area. The left side is fixed by a bolt and the right side can be adjusted by a bolt on the right rear of the race car. If you look at the rear window of these cars you will see 2 holes on the right rear top one is the track bar and the other is wedge. If the car is loose in the corner you would go down on the track bar or use this to remember screw it to the ground.

Now wedge is used to change the wedge or weight of the corners of the car, to try to explain this the second hole on the right rear of the car would add weight to the right rear of the car making it turn better and the hole on the left side of the rear of the back window on the car adds more to the spring on that side making the car tighter. The change is done by the jack bolt either compressing the springs or decompressing them.

I hope I didn’t muck this up too much, I never thought it would be hard to explain.

Now I want to talk about two more aspects to adjust the handling of the car, one is tire pressure and the other is grill tape. I know there are many ways to adjust a cars handling but still the science eludes a lot of teams.

Tire pressure is fairly simple to understand, if the car is tight add more air usually in half pound increments and to the right rear, if it is tight then take some out. This is one of the reasons it is important for the driver to communicate with his crew chief prior to coming in to the pits. The crew chief and his engineers can decide what adjustments can be made to the car to fix the condition the driver is complaining about.

Grill tape is multi functional, on cold days more tape helps the engine reach prime operating temperature and it helps pin or hold the nose to the track if the car is tight this will help it turn better. But then if you have a cold day and a loose car what do you do? Well you try ever other fix first before you remove tape. But when it is cold rarely do you have a loose car. A cold track has more grip and usually you have a tight car.

There is so much more to setting up a car and keeping ahead of the changing track conditions but I wanted to keep this as simple as I could.

Next article I will discuss tracks and why each is different.

Other NASCAR Articles I have written:  

Athletes

NASCAR: Terminology of the Sport 1