This diagram illustrates the action and reaction of antidive forces. The braking force tri
If we arrange our control arm angles, from a side view, for antidive, then as the car dives the upper BJ would move to the rear and the bottom BJ would move to the front. Since the braking forces are in the opposite direction, there is a serious resistant force created which helps prevent the front suspension from moving in compression too quickly while braking.
The amount of resistance is directly related to the degree of side view angle we put in our control arms and the amount of brake force used. The left side suspension usually is designed with about half the angle of the right side in a conventional design. For the Big Bar, Soft Spring setups, teams often introduce Pro-dive into the left front suspension to encourage rapid dive on entry to get the left front down quickly. I don't really encourage that method.
Antisquat results from the third link trying to straighten out, or become more horizontal as the car accelerates and the rear end desires to rotate. The more third link angle you have, the more antisquat there is. The lateral location of the third link can affect the distribution of load among the two rear tires that results from acceleration and antisquat.
Aero is the very last thing you need to think about. You might not need the aero efficienc
Antisquat is detrimental to corner entry. So, there is a limit to how much you can get away with and still have a decent corner entry. Roughly 8-10 degrees of third link angle is sufficient to promote antisquat and not hurt your corner entry.
10. Aero Package
The very last thing you need to worry about is your aero package. I'm not saying this is not important to some degree, but on short tracks I would stress that aero downforce is over-rated in most cases.
The reason I say that with confidence, is because I have gone up against more aero efficient cars with setups and body configurations that were aero-deficient and still out ran them. Still, teams want the most they can get out of their cars and if all of the above nine items are in order, by all means, go ahead with aero tweaking.
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. Remember that drag is an important aspect of aero design. Do not seek aero downforce at the expense of aero drag increase.
Conclusion
No matter which stiffness you decide to go with, the most important aspect of setup is balance, and you achieve that balance with the correct combination of springs, moment centers, sway bars, and load distribution.
It may take a few test sessions to help you determine your balance, but if you observe the indicators correctly, then tuning the car for dynamic balance can be done. Then all you have to do is maintain that balance throughout the season and that means resisting making changes that take you outside that envelope. Good luck.