Chassis 101: Kenny Wallace's setup tips

By By Kenny Wallace, Special to Circle Track Magazine
September 27, 2001
9:52 AM EDT (1352 GMT)

I can still remember sitting in study hall in high school trying to figure out what makes a race car go around a corner really fast.

Growing up in a racing family here in St. Louis, Mo., you really had to learn to do things on your own.

St. Louis was not your typical race town, so I spent many nights in a garage building asphalt cars, dirt cars and every once in a while we would put a roll cage in a drag car. Heck, we even built trailers?anything to make money.

Kenny's chassis basics  Families: The Wallaces  Circle Track Magazine

The name of the place was Poor Boy Chassis, and my brother Rusty owned it.

Everything I did was like going to college. Rusty would start out by always making me keep the shop clean -- which I didn't like to do -- loading the truck and trailer and so on.

If I was going to be a racer -- a true racer -- it meant I had to learn to do it all so I could never have anybody tell me I didn't know anything about racing.

For me, just being part of the race team was never enough. I knew it was important to make sure the car was built right and for everything to stay bolted on the car properly.

But I wanted to be able to talk to Rusty and my brother Mike at the track to help it go around the corners as fast as possible. I guess if the corners hadn't been there, I would have gone drag racing!

So, the knowledge I have gained comes from racers like my brothers, Larry Phillips, Dick Trickle, Pete Hamilton, Bobby Allison and many more along the way.

I know there are textbooks about how to set up your chassis when you first get started in racing, so the one I'm getting ready to give you, I guess, is my own.

The really neat thing about racing is that if you don't agree with anything you read here, that's OK. That's why there is competition. I would like to share some of the chassis setup tips I've learned from the greatest drivers in the world.

Making sure your frame height is correct at all times is one of the basic steps of chassis setup. Measuring off a common mark (the paper on the fender) at all four corners is one way to keep the frame where it needs to be.

Let's start with the rollcage. A lot of people build race cars, so pick one you're comfortable with. Or, if you're like me, grab the tubing off the rack and build your own. After years of racing, I've learned there are differences in where all these bars go and what they all mean.

Some let the car flex, some make the car stiffer, but it's the car builder who puts all of them in. Chassis builders change from season to season, but most of them are really knowledgeable and stay on top of their game.

Once you've ordered your car, it comes as a rolling chassis or a complete car. Let's assume for now that the car is finished. The first thing you have to do is go to the manufacturer and find out what all the frame heights are (LF, RF, LR and RR).

Take a tape measure and make sure all four frame heights are where they need to be, measuring from the ground to the bottom of the framerails. The reason for this is to ensure all the geometry on the corners is in the proper place.

The next thing to do is add weight to the car according to the specific rules of your track. When you add lead to a race car, don't just add it anywhere. Think about where you're putting it. Weight likes to be on the left side. If you can't put any more weight on the left side, start putting it in the area of the car I call the "polar moment." It is just to the left of, and slightly behind, the transmission. This is where the car has the least movement.

Here is the simplest and easiest way to measure frame height. Measure from the ground to the bottom of the framerail on all four corners. When making wedge adjustments, remember to counteract the addition with a subtraction on the other side.

The next thing to do is square the car up. Make sure all the wheels are headed straight in the right direction. There are several ways to do this, but the correct way is to find a constant area on the car.

If you use the left-side framerail, use a string or straightedge to align your rear end. You can line up the rear end with the front tires. To start, you want the car to be perfectly square, with all tires headed in the same direction.

You don't want your car to look like one of those old Chevy Novas going down the highway with the tires heading one way and the body heading the other.

Now comes the critical part: bumpsteer. You will need a bumpsteer gauge to adjust this. What you want to accomplish is to have both front tires travel straight up.

To see the bad side of this, imagine you are driving down the highway and rolling over bumps on the road. Your tires travel in instead of straight up, which leaves you with no control over the front end. Using your gauge, a good starting point is to make sure both front wheels traveling in 2 inches go out 10- to 20-thousandths of an inch.

It's now time to adjust your wheel weights. First, make sure all your tires are set to the correct air pressure and the car is full of fuel and all fluids. Next, put the car on scales to make sure all the wheels weigh what we want them to weigh. The most difficult thing at this point is keeping your frame heights adjusted.

While adjusting your jack screws or coils, remember that the best way to keep your frame heights in order is to use all four corners of the car. For example, if you need more wedge, put a half-turn down in the right front and left rear and a half-turn up in the left front and right rear. This will keep your car at its recommended frame height.

Adjusting the sway bar, which is located behind all the brake ducting, is an essential part of setting up your car for the track. Adjusting the sway bar is one of Kenny Wallace's primary chassis tips for good setup.

Finally, let's go to the front tires and adjust the toe. A good place to start is by taking the left-front tire out straight. Then go to the right front and toe it out 1/8 inch.

Always, the last thing to do is set the sway bar. Make sure the driver is in the seat and the sway bar is neutral to a little bit of load.

Remember, along the way we all become smarter about a race car. These are purely starter tips -- the basics of bumpsteer, toe-in and all the adjustments.

When you show up at the track, I know the excitement of racing will be in the air. Try to stay calm and concentrate on your driving. Most of all, when your car doesn't do what you want it to, remember how hard you worked at the shop.

Don't forget all the adjustments you have on your car. I can still hear Rusty telling me, "There are a lot of good drivers who can drive, but the ones who can set their cars up will win."

Kenny Wallace is the driver of the No. 1 DEI Chevrolet in the NASCAR Winston Cup Series and was also crew chief for his brother Rusty's drive to the 1983 ASA national championship.