Steering and alignment settings (part 2 of ?)

"Of course... a child could do it."

It's amazing how things that were as alien to me as brain surgery a year ago, now seem like child's play in comparison. Such is how it goes when there's no one around to teach you this crap and you have to stumble through it yourself.

A while ago I was having a hell of a time sorting out what various alignment settings (namely toe) really do for turn-in response, stability, etc. Limit steering settings made a hell of a lot more sense to me in terms of getting the inside and outside tires working the way you want them to.

As usual in motorsport "engineering" there is a lot of hand waving and not a lot of example data, nor explanations of how to come to these conclusions. Even with as much as I like Carroll Smith's books - including 'Engineer in Your Pocket,' they do a lot to lay out the "what" and not so much the "why." In my opinion, if you're an engineer and someone is laying out a lot of "what" and not a lot of "why" then there should be red flags going up in your head, and the needle on the 'BS meter' should be steadily rising.

How then do we put some real numbers to everything? Simulate the damn thing! It's almost too easy. The equations of motion (sideslip rate, yaw rate, etc) are no big mystery. Figuring out what exactly you want to look at to quantify transient response does require a bit more thought, unless someone has already thought of it for you. Hint: there are a variety of papers in the public domain on this topic. Bottom line, it's super simple to run some combinations of front and rear toe and see precisely what they all do to vehicle response. Very enlightening. Can also probably see the effect of roll stiffness, and how it approaches a rigid body model as the spring rates approach absurd (read: FSAE) levels.

I may or may not post those results up. If I do they will be completely un labeled and with no legend... but if you want to research it on your own it's pretty straight forward.