I think I got something wrong in the last post.
I said “However, the sway bar, unlike the springs, acts across the car to create an increase in the total weight transferred from the inside to the outside, which tends to decrease total lateral G capability.”
Did you agree or disagree?
Some people have definitely thought this in the past. They (and I) may have been misinterpreting such statements as this, from Carroll Smith, in Tune To Win, page 38: “…the stiffness of the anti-roll bar will both decrease roll angle and increase lateral load transfer.”
We’ve got to be careful with that statement.
The sprung mass rolls. If there is no sway bar, the inside spring extends, reducing weight on the inside tire. The outside spring compresses, increasing weight on that tire. If you could put a scale under each wheel you will measure what looks like a “weight transfer”, but it’s not, really. It’s a differential in forces at the tires and it will disappear once the car stops cornering. The amount of force differential is controlled by the mass, the lateral acceleration, the track distance and the moment arm which is the distance from the CG to the roll center. The amount of roll doesn’t matter. The stiffness of the spring doesn’t matter. The existence of a sway bar doesn’t matter.
If there is a sway bar, some of the roll energy goes into it instead of the springs. The roll is reduced, but that energy creates another force differential at the tires. The sum of the spring differential forces and the roll bar differential forces exactly equals the previous amount with springs alone.
So, there is no negative effect on maximum cornering force due to using a stiff roll bar. There is no increase in the total amount of weight transfer, or what I call force differential.
But, during the transient, that is, during turn-in while the lateral-Gs are rising, roll stiffness from springs and bars is a good thing because it makes things happen faster. Energy absorbed by the shocks is a good thing as the effect is to (temporarily) increase roll stiffness and make things happen even faster. The force differential at the tires is going to do what it’s going to do, which is to decrease the maximum lateral-G capability due to the shape of the tire load sensitivity curve. Not much I can do about that in Street class other than set up the car as low as possible. Or, go on a diet and get a lighter helmet!