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THE RACERS EDGE
ARCHIVE 09-01-00

OVAL TRACK SETUP - Part One
A Beginners Guide To Oval Track Racing

By John Nuttall, Raceway Kart Association

“There are no real secrets in racing. The secrets are just things you have not figured out or heard about yet.” Source unknown

In this two part Special Report, I will be discussing basic (LTO) oval track setup for pavement and dirt.

The topics are:

Selecting and aligning wheels and tires
Understanding balance and weight
Positioning the seat
Scaling and adjusting weight
Basic adjustments you can make at the track

WELCOME TO OVAL TRACK SETUP!

The information herein is intended to be used by new and inexperienced kart racers and is designed to teach the basics of LTO or “left-turn only” oval kart setup. We are sharing our knowledge and experience so you can run up front and win! The information will show you how to setup an oval chassis or a standard straight up chassis to run ovals, dirt or pavement, competitively.

The article will expose karters to the how and why of oval track setup. The first point that we are going to cover is that most karts can be setup to run competitively on an oval track. We have all heard you can’t set up a straight up chassis to run ovals competitively. Not true! Yes, there are many advantages to a kart chassis that was built to run ovals only, since many of the adjustments are designed in. But, on a straight up chassis, you can make adjustments to the kart setup to give it a left turn bias.

The most important thing you need to know about oval track racing is that cornering is everything! You cannot go down the straightaway fast if you cannot get through the corners. We are going to learn how to adjust your kart to improve cornering speed and handling.

WHAT ARE WE GOING TO COVER?

We are going to discuss the basic track setup for dirt/clay and pavement racing. We will cover balance and weight, selecting tires and wheels, aligning the tires, positioning the seat, scaling and adjusting weight.

Once you are at the track, changing conditions mean changing set ups. We will cover the basic adjustments that you can do between practices, heat races and at intermissions, which may give you that extra boost you need to take the checkered flag. We will teach you how to make a “push” go away and how to tighten up a “loose” kart.

Getting power to the track is essential if you are going to run up front. Each racer in a class has essentially the same horsepower – but what good is power if the power is not helping the kart move forward? You will learn how to turn horsepower into speed.

THE BALANCING ACT.

Basic kart setup is a balancing act. Your goal is to select the perfect balance between forward traction and turning traction.

If you have too much forward traction, the kart does not turn in the corners. A “push” causes the front of the kart to slide out in the corners.

If the kart is setup with too much turning traction the back end of the kart slides out (loose) causing the rear of the kart to slide out in the corners.

We will explain push and loose in more detail later. It is important to remember that anything that improves forward traction hurts turning traction. You need to find the perfect balance.

Our goal is to increase corner speed so we can get down the straightaway faster. The kart with the most speed exiting a corner should be the first kart into the next corner. You can have all the horsepower in the world, but you need to get it to the track to be fast!

UNDERSTANDING BALANCE AND WEIGHT.

Just so we are all taking about the same thing, the basic terms are:

Front weight: This is the amount of weight on the front tires. Front weight affects how a kart turns.

Cross weight: This is the diagonal weight on the right front and left rear tires and vice versa. Cross weight affects how a kart turns.

Left side weight: This is the amount of weight on the left side tires. Left side weight affects side bite and how much weight is transferred to the outside tires.

Stagger: This refers to the difference in size of the rear tires. Stagger affects how a kart rolls in the corners.

Weight percentage: This is the static weight of each corner of the kart. Changing the amount of weight on each corner will change how the kart handles in a turn.

Ideal weight percentages:

Front - 43-45%
Left - 53-56%
Cross - 52-54%

What do these numbers mean? For example, if you are racing the Briggs Light class at 305 pounds, your corner weights should be:

LF = 68 pounds RF = 68 pounds
LR = 95 pounds RR = 74 pounds
Total = 305 pounds

Front percentage = 44%
Left side percentage = 53%
Cross weight percentage = 54%

This is a very good place to begin for most oval tracks.

Now, let’s start putting all this information to work setting up an oval kart chassis. The static corner weights tell what each corner of the kart weighs when the kart is “at rest”. In a turn, the centrifugal force transfers the effect to the outside (right side of the kart) and forward. Too much weight on the front makes the kart feel loose. Too much weight on the rear makes the kart push, not turn in the corner.

SELECTING THE PROPER TIRE

First, we need to choose the tires you want to run. Selecting the proper tire depends on your driving style and approach to the race track. The driver who wants the kart to run loose will start with a harder compound tire. Drivers who want the kart to have a lot of turning traction will start with softer tires. Some tracks make the tire selection easy if they have a tire rule. Look around at the track at what tires the front-runners are using. That’s a good place to start.

Softer tires give you more grip in the corners, but they wear faster. Too much grip can make the kart tight. A condition when you lose speed going through a corner. On shorter tracks and low traction tracks, softer tires are the tires of choice.

Harder tires wear longer and they maintain driving characteristics for a longer time period. The lower grip may make a kart looser in the corners. On faster, long tracks, harder tires are the tires of choice.

Not everyone at the track will make the same decision on what kind of tires to use. There is not always one right answer to the tire question. You may be able to make a hard tire or soft tire work on the same track depending on how you set up a kart. I guess that’s part of why karting is such an interesting sport.

TIRE AND WHEEL ALIGNMENT ON THE KART

When selecting tire and wheel combinations, start with the right rear tire on a wheel equal to the width of the tire. The left rear wheel should be approximately 1 inch wider than the tire. This combination will give you approximately ½ inch of rear stagger. We will discuss stagger later in this report.

Seniors should run wider tires and Juniors a little narrower. Senior class drivers should start with a 7 or 8 inch tire on the right side and a 6 inch tire on the left rear.

The front tires are a bit easier to figure. They should be mounted on wheels equal to the width of the tires.

The placement of the wheel/tire combinations on the kart is the next step. Start with the front wheel assemblies in the middle of the spindles. This will give you lots of adjustment. Adding and subtracting spindle spacers on the front spindles will allow this.

Next are the rear tires. Start with the left side of the kart. Align the outside edge of the left front and the left rear tires. Now the right side. Align the inside edge of the right front and right rear tires. This is one area that is easier on an oval chassis because the rear of the kart is offset allowing the rear wheels to be adjusted. Those of you with straight-up karts may have a little trouble here, so you will need to take a little time and get as close as you can with the rear wheel adjustments.

After the rear wheels and tires are adjusted, it’s time to set the front-end “toe in”. Toe-in is when the leading edge of the front wheel/tire assemblies are slightly turned inward. These adjustments are made by rotating the tie rod ends slightly. (Editorial note: For safety sake, make sure you have at least twice the diameter of the tie rod threaded into the rod end. Example: ¼” tie rod = at least ½” of rod threaded into the rod end. If, when doing this, the tie rod is too short, don’t take a chance. Use a longer tie rod.)

With a tape measure, yard stick or toe-in tool, measure the distance between the back edges of the front tires, then measure the front edge. Adjust them until they measure the same. Now, adjust the toe-in slightly to 1/6” . As you get more comfortable driving ovals, you may want to try a little tow-out on the left front tire.

Now set the “camber” to the factory specifications, if it is adjustable. Camber is when the wheel are closer together at the bottom than at the top.

The next step - the king pins. Center the spindles with spindle washers. This will give you more adjustment for the front end weights.

When this is all completed, the front tires will have equal amount of weight while the left rear will be much heavier than the right rear.

Basically, the same kart on the same track would be set up narrower for harder tires compared to softer tires. In addition, your wheel base will be narrower if you run on dirt rather than asphalt.

Next month: In Part 2, we will discuss the basic set-ups, how to make adjustments, and much more.

END

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