1935 Miller-Ford Indy 500 Race Car

That's neat! What material did you use for the torwion bars?

Looks great. 83 lb/in may be about right

Charles, I ended up going with a 5.5" arm on the torsion bar. That means the wheel, and the actual point of force on the axle, will be about 7" outboard of the attachment point of the arm to the axle. What effect, if any, will this have on the suspension?

Lowell, It's a secret for now. I want to do some testing before I reveal it. If you look closely at the picture, you might see a name brand on the bar.

Offsetting the end of the torsion arm from the actuation point at the wheel can complicate the math. I think you will be OK.BTW, all steels, regardless of hardness, have the same torsional stiffness. The harder steels/better alloys will last longer as they have a higher tolerance for stress cycles. I'll make my first torsion bars from AISI 1018 & if they lose their "springiness" I'll move on to AISI 4140 HT'd to 300 HB.

Well, I'm kind of at the point of no return now. This is either going to work or it's not. Did you see in the picture, the anchor end of the torsion bar is adjustable. I can use it to adjust the ride height, or to jack weight into one corner or the other. If it's worth doing, it's worth overdoing. I can also adjust the length of the links, because they just 2 heims, a male screwed into a female.

The traditional way of adjusting ride height on a parallel torsion bar midget is to index the arm or the stop to get the height "right." One side is directly mounted to the "bird cage" [rear ax;e] or front axle bracket. The other side has an adjustable length link [made of two heim joints as you have done] so the car can "roll" through the corners. It is a time tested suspension that scales up to champ dirt cars and down to midgets. TQs, and Half midgets. If you have a race car museum nearby you can learn a lot just by looking. Cross torsion bar systems are slightly different since they use a panard bar for axial location of the axle.

How much do you figure all of this is going to weigh?And how will that compare to the traditional buggy spring??Brian

Generally speaking torsion bar systems are lighter than leaf springs and about the same as coil springs over tube shocks. For torsion systems you can save weight by making the arms and stops from aluminum

Not to steal Rick's Thread here, but what he is doing here may be the way I will go to make room for my in the Belly Tank.Brian

Brian, I don't think it weighs any more than leaf springs do. I only did it this way so the suspension willl fit inside the bodywork. Look at a 1935 Miller indycar and imagine it with leaf springs showing. It would ruin the clean look.

I hear you!