The front moment center location...
The front moment center location controls much of the dynamics of the front suspension.
The front MC is the bottom of the front moment arm. Its position determines the length of the moment arm and the efficiency of the front suspension. If the front moment center were located too far to the left, the front suspension would roll excessively and the right-front suspension travel would be excessive. This will cause the right-front tire camber to change too rapidly and that tire would lose grip, a condition usually described by the driver as the car "falling over" on the right front. If the MC is located too far to the right, the front end will be overly stiff and not want to roll, and the front suspension will not work along with the rear. This is much the same as having stiff springs up front.
The static front wheel cambers we run to maintain proper tire temperatures across the face of the tread is an indicator of the balance of the setup and/or possible problems with camber loss or gain at the right-front wheel. Running excessive camber on the right front tells us that tire is working too hard.
This invisible intersection...
This invisible intersection point is the bottom of the moment arm and should be designed correctly for each type of race car for each particular track.
For any type of racing, be it dirt or asphalt, high or low banking, we should never need more than four degrees of negative camber at the right front. Teams that run 5-6 degrees of static camber are usually running setups that are unbalanced and that cause an excess amount of weight transfer to the right-front tire.
Just like the front MC, rear MC is the bottom of the rear moment arm. If the Panhard bar is set too low for the springs selected, the rear of the car will be too "efficient" and want to roll more than the front. This causes a tight condition due to excess weight transfer to the right-front tire.
The Panhard bar, J-bar, leaf spring, or Watts link heights determine the rear moment center height. Since the MC is the bottom of the moment arm in the rear of the car, its height determines the moment arm length. The longer the moment arm (due to a low MC height), the more efficient the rear suspension will be and the greater roll angle the rear will want to attain. As we raise the rear MC through whatever means, we shorten the rear moment arm and decrease the efficiency of the rear suspension causing it to be stiffer, similar to putting stiffer springs in the rear.
The car "feels" the rear moment...
The car "feels" the rear moment center halfway between the tops of the springs and at its height calculated from whatever lateral locating device might be used. The rear MC is the bottom of the rear moment arm and the height of the MC regulates how much roll angle the rear of the car will desire to go to in the turns. By raising and lowering the rear MC, we can regulate how the rear matches the front to balance the setup.
The changing of the rear MC height is one of the primary tools we use to help create a balanced setup where the two ends of the car are working together in harmony.
Having an excessive amount of crossweight percent, or bite as it is referred to in dirt racing, causes too much weight to be supported by the left rear and right-front tire and can cause a car to be tight in, through the middle, and off the turns.
Running a crossweight number that is too low is a distinct indication of a tight car. If a car needs 51.2 percent crossweight to have proper weight transfer, and is only running 48.8 percent, the team has needed to take cross out of the car because the setup was tight.
There is an optimum percentage of weight supported by the cross corners (right front and left rear) that will make the car neutral. Remember, a neutral car is not necessarily a winning car. It must remain neutral throughout the entire race.
If the steering system creates either too much Ackermann (where the left wheel steers much more than the right wheel in a left-hand turn), or reverse-Ackermann (the reverse effect), the car will have too much toe-out or toe-in at the point of mid-turn. This will cause the front tires to desire to go in different directions and they end up fighting with each other. This will cause one or both of the front tires to lose grip, which makes the car feel very tight to the driver.