Originally Posted by Epstein

y-axis is the wheel height. Positive numbers are wheel going up (compression). x-axis is toe-in (positive numbers). Basically what you're looking at is how the toe changes versus wheel height. This is called bumpsteer. You can see that the S14 line is a lot more up and down than the S13 line. That means that the S14 subframe (atleast in this setup) has a lot less bumpsteer than the S13 subframe. Find the point at the top where the wheel moves between 1.5 and 2.0"... the S13 has twice the toe-in gain as the S14. As far as these numbers in absolute terms, I generally run .125" to about .187" of toe-in in the rear. That would be at 0" of height on this chart. At 2" of wheel compression, that amount of toe-in would double with an S13 subframe (2" = an additional .200" of toe). If I had an S14 subframe, the toe wouldn't change as much.

So what does all that toe-in mean? Think of taking a left hand turn. Your car rolls to the right. Your right tire is in compression and your left tire is in droop. So lets say you've got a ton of roll going on and you're compressed 2" on one side and in 2" of droop on the other. Well the right wheel is going to point in (left) and your left wheel is going to point out (also left). What this serves to do is to steer your car into the turn. By feeling, what it's doing is fighting oversteer, or creating understeer depending on how you look at it. There are other forces acting on these subframes to counteract that, though. That's a different post.