Rear suspension: 3 link with transverse spring?

Aerostars use a 3 link rear suspension. The upper had 3 mounting points in an "L" shape.
Some Alfa Romeos also used it.



Your traverse spring should work as well as their coils.

 

Dick:
Not to get into a whole discussion, but I'm surprised you would say that the original design (2-link mounted on the frame rails) was fine, then offer "change of pinion angle" as the reason my new setup won't work. Or, maybe I should say that I'm not surprised.

• Are you implying that the pinion angle does not change in a 2-link? Because rough calculations say that the angle of the pinion in my original 2-link configuration would have changed more than 6 degrees with 4" of travel at the axle.
• Per my original post, I recognize that top and bottom links are at slightly different angles and lengths, but given the amount of suspension travel (lowered hot rod), the change in angles will be negligible in my opinion, as i said, according to crude calculations and measurements during mock up. Negligible, I'll define as a change of 1 degree or less during 4" of travel measured at the axle. Additionally, the change in angles will be far less than in the 2-link configuration.
• lastly, i don't claim to be a suspension expert by any stretch of the imagination, so maybe I'm missing something, but there are any number production examples out there w/ far larger differences in upper/lower link lengths. And I wouldn't consider them ill-handling by any means. Terry R offered one example in the Aerostar. 64-72 El Camino/Chevelle as well, and I believe all GM A and G bodied cars too.

So, are you simply offering opinion, or can you give me some numbers/reasons that this isn't equal to or better than the original 2 link configuration, or the productions designs referenced above? Again, I very well may be missing something.

 

Scott, Your rear axle is located on the bottom control rod that is a clevis pivot, the top V rod is also mounted on a pivot neither operate on the same concentric arc swing due to the position of the front mounts. The upper rod tips the axle fore or back depending upon the swing travel. Now combining this with essentially an upper mount of the spring you have 3 mounting points that have to work together, in your case I dont think they do. To do a trial test set you frame on jack stands at ride height, unhook your rear spring shackles on both sides and set your pinion angle. Place a bubble level on the pinion snout and raise and lower the rear axle housing 4" travel and you will see how the upper rod effects the pinion angle. Now as you are doing this reference the angle of the axle shackle stud to the spring eye stud as you repeat the operation and you will notice the twist or bind created in the rigid spring.

What you have created is not a 3 link suspension but a 5 link. The lower bars are 1 and 2, the upper mounts is actually the spring and spring perch, 3 and 4 thus making the center mount on the pumpkin 5.

Your reference to the coils spring cars is not the same because the coil spring allows fore and aft movement because of the spring design and the springs actually float in the mounting pads. Thus a 4 link or 3 link with out a bind is possible.

The original radius rod set up that was on your car operates on each side from one pivot in the front and fixed rear mounts almost like an old Ford, yes the pinion angle changes but slightly due to the single radius distance formed by the radius rod.