Fine-Tuning Your Chassis At The Track

Caster/Camber

Getting the tires to contact the pavement correctly isn’t as simple as filling a tire with air and mounting it on your race car. A change in the camber setting can get the results you’re looking for. Using a pyrometer, take readings on the inside edge, the middle and the outside edge of the tire to determine the amount of heat across the tire. The hotter the temperature, the harder that section of the tire is contacting the pavement. When running on a short track, the optimum temperature should be 10-15 degrees hotter on the outside of the left front and the same on the inside of the right front. With this information, the camber setting can then be adjusted to achieve the desired tire-to-pavement contact.

Toe-In

Don’t forget, when making caster/camber changes the toe-in measurement can change as well. Always check the toe-in after making caster/camber changes.

Tire Stagger

Because the inside tire has a smaller diameter circle to travel while going through a curve, it is imperative that you get the tire stagger set correctly. Having the incorrect stagger will make for an ill-handling race car. If your car is tight in the middle and coming off the curve, then an increase in stagger is needed. If it’s loose from the middle out, reducing the stagger will help. Minimal stagger adjustments can be made by adjusting air pressure, but anything over a quarter-inch requires changing the tire size.

Sway Bar Adjustment

When you’re coming through a turn and start to accelerate and your car starts to spin the rear wheels without lifting the pedal, what can you do? The sway bar can be the answer to your problem. Increasing the sway-bar tension will add bite to the left rear tire, reducing the tire spin. Also, if the race car is rolling or leaning in the turns, an increase in tension will help. Having too much tension will also create a problem; this will make your race car push off the corners. The trick is to have enough sway-bar tension to stop wheel spin without creating push.

Panhard Bar

If your race car is tight or loose throughout the entire corner, not just on entry or exit, an adjustment to the Panhard bar could be the key to correcting this problem. The Panhard bar is located in the rear of the race car connected to the left side axle tube next to the wheel and to the race car’s frame on the right side behind the wheel. To loosen the race car up through the entire corner you will need to move the Panhard bar up and tighten the opposite bolt.

Brake Bias

Front or back, how does this effect your race car and where should there be more brake? If your car pushes when applying the brakes while entering a curve, then you have too much front bias. Increasing the rear brake will help decrease this brake push.

There are two types of brake bias adjusters: one is mechanical and the other is hydraulic. The mechanical has a bar that goes between the two master cylinder pushrods and is adjusted from side to side, changing the amount of pressure applied to the front or back master cylinder. The hydraulic type increases or decreases the amount of fluid (hydraulic) pressure going to the rear brakes by restricting the brake fluid flow.

So when handling gremlins are plaguing your night, use these quick-and-dirty tips to correct your car’s behavior. The results will surely please you, and remember where you got them!