V1.3 Dec 31 2007
This is a work in progress, and it has been a very long time coming. I intend on working on it for the next little while, dumping as much of my brain and hard-earned knowledge into the public record. It is, however, NOT public domain; I reserve the copyright for myself. You may NOT duplicate this elsewhere without my express permission - and this is the age of Google, folks, I WILL find you if you post it elsewhere. Otherwise, read and enjoy, and put this all to good use. Go fast!. DG
When you set the spring rates according to natural frequency, you probably couldn't limit the max roll angle to where you needed it with just springs without getting into stupid-high natural frequencies, so you probably need sway bars. Adjust total stiffness to keep the roll angle in check, adjust stiffness bias to set mid-corner balance to minimal understeer and a little entry oversteer.
A neat trick is that if roll stiffness distribution exactly equals weight distribution, all else being equal, that makes the car neutral. So set the roll stiffness distribution a tick rearward to promote a little corner entry oversteer and you're in the ballpark.
A slightly - and I mean slightly - tail-happy car is faster, especially in slaloms, but it can be easily overdone to the point where the car wants to snap-spin on corner entry. That's not fast; it hurts driver confidence and limits his ability to really attack the course. So a little bit of oversteer, but not too much.
I've had a number of people ask me if I included the sway bar rate (along with its motion ratio) to work out natural frequency and subsequent damping - no, I did not. The contribution of the roll bar to overall spring rate is so small - and it isn't always there - so it didn't seem worth trying to chase a force change that small. If you have sway bars so stiff that they are affecting damping... I think you need to stiffen up the springs and lighten the bar. Roll bars should be trim controls, not major players.