[Nereth]

Originally Posted by KiwiBacon

Lets start with the errors in this paragraph.

Firstly, the roll axis slopes up towards the rear on every vehicle I've looked at. That is, the rear suspension roll centre is higher than the front.
The roll axis is the result of the roll centre, not the other way around.
This is another reason why many production vehicles have sway bars fitted to the front and not the rear.

I had always thought that it was the other way around, but, if you say so I will strike that from my list of arguments.

Originally Posted by KiwiBacon

Secondly, talking spring rates doesn't mean much without including the sprung weight at that end. You probably don't realise but the natural frequency of the suspension matters most and rear suspension is often tuned to have a higher frequency than the front. One of the goals is to prevent see-saw pitching.

I am aware of that. See my post above, even with the rear natural frequency slightly harder, the lack of weight is enough to make the rear springs rate softer in terms of force per distance.

Originally Posted by KiwiBacon

You do not need a "stupidly hard bar" in the rear, I have no idea where you got this idea from, but it possibly stems from you getting the roll axis wrong above.
As I've said, normally you need no sway bar in the rear, if you do need to add one to tip the balance, it's rate does not need to be high at all. One of the purposes of a sway bar is to cause faster load transfer to the outside wheels.
The higher roll centre of the rear wheel already causes faster load transfer without needing additional roll-stiffness to acheive that.

If the roll center is indeed higher in the rear, then admittedly you could soften the sway bar somewhat. However, how much? It would probably go beyond my interest in this discussion to try to make a similar analysis to the above while including suspension geometry.

Originally Posted by KiwiBacon

There's a catch with applying theories, the catch is you need to understand them well enough to apply them correctly. I'm convinced that on this subject you don't.

And I'm convinced I do. Without going through and checking everything, the only new peice of information I ahve been introduced to here is that the roll axis usually slopes upwards rather than downwards. Other than that, all the disagreements have either been 'I have driven a car that drove better than another car', or corrections that winded up not correcting anything (saying the rear wheel needs a higher natural frequency, while ignoring the fact that the rears reduced mass makes that happen at a lower spring rate). Oh, and questions of magnitude, which really have nothing to do with the understanding of the theory.