Roll centres + Rubbish saloons

[phoenix]

Originally Posted by Denis Bassom

I thought the roll centre was dictated by the point that the panhard rod crossed the centre of the diff housing and hence also reduced when the car was lowered?

That is only true when a panhard rod is added to a simple cart-sprung rear axle. As soon as you add other links (in your case four trailing arms) then the rollcentre loaction is dictated by other factors. Page 34 of Fred Puhn's book gives the details, which are to complex to descibe on here with just words. Suffice to say, that lowering the rear of a five linked axle can actually raise the roll centre considerably, thus increasing roll resistance and giving a previously neutral or under steering car oversteer.