Roll Centers and CG

[C M Smith <cmsmith@domain.elided>]

An astute reader noticed that probably (or possibly) lowering the roll 
center might not be  a way to reduce roll. Indeed, this is true.

Roll relates to the relative positions of the roll center and the center of 
gravity of the vehicle (CG) which create a moment causing the sprung mass 
to roll around the roll center. The lower the roll center, the bigger the 
moment, the more the sprung mass rolls. Experiments have been done to 
create a vehicle with a very high roll center which roll inwards when 
cornering. A bit disconcerting and of dubious efficiency.

Moral of the story is don't mess with suspension geometry unless you know 
what you're doing. Generally, lowering the roll center without lowering the 
center of gravity requires that you stiffen the spring rate in roll to 
preserve handling characteristics, let alone try to improve them.

My 0.02, from a guy who drives stock vehicles all the time, most 
modification I've done is Bilsteins on some woefully underdamped SAAB 
products, oh yes and better tires, let's not forget the cheapest and most 
effective way to improve vehicle handling...the best tires you can afford.

Cheers

Michael


Michael Smith
Calgary, Alberta
Canada
91 Alfa 164L, White, original owner

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