IRS alignment setting for wide rear tires

[RonRyon]

I’m not talking about torque causing the lifting action but rather the force transmitted to the TA from the wheels which push the car forward. Physics would say that the force exerted by the wheels to the chassis through the TA has two components, a horizontal force and a vertical force. The horizontal force pushes the car forward and the vertical force pushes the car either up or down depending on the angle of the TA. The amount of the vertical force is dependent on the angle of the TA relative to the horizontal.

Or, a another way of explaining it --- looking at the passenger side for example, if the TA angles down to the rear, the force exerted by the wheel will try to cause the TA to move in a counter clockwise rotation. In order to do so it must lift the car.

It would be easier to explain this with a drawing but I don’t know how to do it on my PC.

Not that it matters, but don’t ladder bars lift the car? I don’t believe I have ever seen a ladder bar design that could push the rear of the car down. Maybe if excessively long, push the front end up and thereby helping weight transfer to cause the rear of the car to squat from the additional load. Also, it seems to me that the counter rotational torque is absorbed by the ring gear in either case (fixed axle or IRS). But then I have been wrong before.

The bottom line is, I think that among other handling problems created when lowering a Bug, anti-squat should also be given serious consideration.

[Bruce2]

Oh yes, of course! There will be a force pushing the TA down due to the forward force on the TA. And the higher the front pivot, the greater the force. When you break it down to the horiz and vertical components its clear.

Ladder bars on American cars do lift the rear of the car. They do it by planting the rear end down harder. Have you ever noticed how some of them don't squat at the line?

[RonRyon]

Bruce, that is what I was trying to say when I said the thing about drag cars being lifted as they come off the line. So, I guess you agree that the angle of the TA can have an anti-squat effect? I have personally observed this on the previous cars that I have built. The benefits were very noticeable and very positive not only for straight-line acceleration but also for overall handling.

[Bruce2]

The only problem I see is that when you raise the inner pivot, you will get positive camber. Raising both will require you to raise the whole torsion housing (a big job). Then it also raises the engine/transmission.

[RonRyon]

The plan would be to raise both the same amount. I'm not using the torsion bars so it will be less complicated. I'll let ytou know how it goes, but don't hold your breath, I move pretty slow these days.