7. Brake Bias

Turn entry on dirt is important and dictates how well we are able to negotiate the middle of the turn. So, we need to evaluate our turn entry characteristics related to the amount of brake bias. We may want to try to solve turn entry problems with the brake bias on dirt.

As we said earlier, I see many top drivers using braking into the corners on dirt to slow the car rather than throwing the car sideways to slow the car down. This technique is used for Dirt Late Models, Modifieds, and Sprint Cars under certain conditions.

Brake bias influence can easily be determined for any race car by entering the corner with medium to heavy braking first and then entering with light braking to see if there is a difference in the cars attitude. If there is, try to adjust the brake bias to improve the entry conditions under heavy braking to what it is under light braking.

Brake bias can also be used between the front wheels. More bias toward the left front will allow the right front tire to maintain lateral grip and help turn the car more so that if it were also trying to slow the car and using up its available grip.

8. Bite off of the Corners

We never seem to have enough bite off of the corners on dirt. The exit portion of the track provides little traction and most corners are usually more flat. We almost always need to develop more rear traction upon acceleration. To give the car more rear traction, we need to understand a little about the dynamics at work on the car when we are accelerating.

We should work to develop ways to create more rear traction on acceleration only so we don't ruin our mid-turn handling. There are several ways to do that without changing the handling at other points around the racetrack. One way is to reduce the "shock" of sudden application of throttle and torque to the rear wheels.

We can use lift arms and pull bars with various stiffness of shocks and springs. More and slower movement is needed for slick conditions and much less movement for the tackier conditions. Another way to gain bite involves the use of a spring loaded pushrod that allows a certain amount of forward right rear wheel movement to steer the rearend more to the left.

Adjusting the amount of loading that falls on the rear tires as the loads transfer on acceleration helps increase forward bite. If we overload one of the rear tires, then we don't have as much grip as if we evenly load these tires.

On the other hand, for very dry slick conditions, it has been shown that putting more loading on one tire will cause it to push through the sand and grip more than if we evenly distribute the loads. That is why loading the left rear works on dry slick tracks.

Much of what you read here has been observed during my three years on Tour to tracks around the country

9. The Anti's

Antidive and antisquat are mechanical influences that can help our transitional phases of entry and exit. We can regulate the amount of both depending on the need. A small amount of antidive on our dirt cars can help prevent sudden nose dive on entry by utilizing mechanical resistance to the downward motion of the suspension.

Antisquat results from the pull bar trying to straighten out, or become more horizontal as the car accelerates and the rearend desires to rotate. The more pull bar angle you have, the more antisquat there is. The lift arm also creates antisquat and can actually lift the rear of the car on acceleration. Lateral movement of the front and/or rear of the lift arm can alter the loading among the two rear tires upon acceleration.

10. Aero Package

Racers discovered the need for better aero designs some years ago. Just look at the way Dirt Late Model bodies have evolved. The front ends are wedges that scoop the oncoming air up and over the car. The wheelwells are shaped to route air out and away from the front tires creating low pressure under the hood and more downforce.

The degree that you need to get involved with aero for your car depends a lot on what you run and where. Aero influence varies with the speed of the vehicle. There is an algebraic increase in both drag and downforce associated with increases in speed through air. That is why a car with twice the horsepower does not go twice as fast.

Try to understand how aero downforce is created and then configure your car so that you take advantage of every area where you could produce more downforce. On dirt, we need the most loading on our front tires that we can get and aero generated load is not weight we have to accelerate.

Conclusion

The ideas we have presented and the methods we preach have a basis. Much of what you read here has been observed during my three years on Tour to tracks around the country. No one has to buy into any of what is presented here, but you do need to think out your particular setup and how you attack your racetrack.

To be more successful, it helps when you get your car setup correctly for the basics of geometry, alignment, and balance. Develop a proper approach to the setups for the tracks that you intend to race at and be prepared and willing to make changes to your setup when the track conditions change. That ideology will never change.