More 1/4 elliptic rear suspension questions

I calculated mine out to just over 1/8" at the extremes of the arc. My father, who is a retired mechanical engineer, said that it falls under the category of "picking the fly shit out of the pepper."

 

Keep searchin, there was another thread on here about 6mos ago where the guy used the spring as a lower control arm and he had bad rear steer from spring wrap - he may not have the exact same geometry as yours but it is a good read and a lot of input, i remember 'exwestracer' and 'dons hotrods' posting a few thoughtful pieces.
I redesigned my quarter-elips into 4link because of that thread.

 

This gets asked often on here....hook the springs up without shackles, jump up and down on the chassis, watch the rear end change caster as the spring grows and shortens. I like shackles, thats how I set mine up.

 

Can anybody post a link to this? I'd like to take a look.

 

I've tried searching "rear steer" and I have combed exwestracers recent posts to no avail, can anybody guide me to this thread? Did the car in question use a torque-tube? Or was this thread posted in "Area 51'?

 

the thread was called 'Technical Quarter Elliptical Problems'...i don't know how to do the 'link' thing. Dick Spadaro made some very good points in that discussion as well.

 

Thanks OJ, I will try searching for that.

 

FWIW heres a few pics of mine that i redesigned because of that thread. I added the lower shackles and control arm that travels on the same plane/arc as the spring. I didn't make any changes to the upper arms.
excuse the honest dust, the shocks were recently added and not complete, bolts are just stuck in place etc - it is under construction.
The spring originally went direct into the bracket on the rear, i made that shackle to go from inside the bracket to outside the spring.

 

Ok, found it. No torque-tube, no panhard bar. Not surprised its wobbling around.

 

oj, on your setup the spring is just a spring and not a control arm so to speak right? I guess Im struggling to see how the shackle doesnt counter act the spring. Like if the car is moved up and down does the shackle just move or can you see the spring move?

Brad

 

I'm setting up a '34 very much like Malcolm's. The spring length change from a full assembled pack, to a lone main leaf fully flat was LESS than 1/8". That will have basically zero effect on pinion angle and will work. Just loking at it, you would guess it to be more length change, but my tape measure doesn't usually lie to me.