Originally Posted by cboy
Sorry if I didn't ask my question clearly enough. I wasn't asking what this setup WAS (it's pretty clearly stated in my first sentence that it's quarter ellipticals) nor was I asking if quarter ellipticals have ever been used on a street rod (fairly common as I also noted in my original post).
What I was asking about is the specific setup shown in the midget pictures with the spings under and the adjuster/controller bar over and whether THAT setup would work on a street car. For one thing, I'm wondering if the lack of any shackle or allowance for spring extension would tend to rotate the axle or cause binding during axle travel. Other questions regarding the geometry may arise as well. But that was the discussion I was looking for.
Yes, it will work fine. The upper control arm takes the front to rear axle locating load off the spring and between the spring attachment and control arm attachment the longitudinal roll center of the axle is maintained, this is the same thing the wishbone in some of the other pictures is doing with an additional piece of structure. Either way works, you just have to be careful to keep the rotation centers of the spring and control arm in the same plane so that the axle isn't pulled, pushed, or rotated as the tire moves it up and down.