[manxman]

Originally Posted by gimp

I don't mean to start any trouble, but how could any of that be correct?

Sure, stiffening up the rear of a car "can" reduce understeer, but how is a bar running from one upper corner of the body to the other, with no triangulation going to do anything but add weight up top?

Strut tower braces were originally intended to reduce the spreading of the upper strut mounting points under cornering load. In this particular case, there is nothing that mounts to those same spots other than the seat belts - no suspension components. Are you saying that under heavy stress the roof skin stretches?

Without triangulation, this piece doesn't do a thing. Take a cardboard box, cut off the top and bottom, and lay it on it's side, so you have a big open square [ ] (much like a hatchback car). If you add re-enforcement from only one side to the other, at the same height, the box will still collapse to the side. Triangulating or cross bracing this structure ( [/] or [X] ) would stiffen the back, but not just adding one bar up top.

If you want to fix understeer, buy a rear sway bar.

You are absolutely correct gimp. But many will scream that you are wrong, simply because all that they read are ads for useless junk instead of textbooks on metallurgy and physics.