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The first question should be IMO, could someone describe and BACK UP at least, with sound reasoning, what actual forces sub frame connectors resist? I am not questioning many many positive reports of thier improvements in ride etc. So are they resisting compression as the rear leafs push forward upon acceleration, are they resisting twist individually, if just under tension we can just use a steel cable, are they preventing a bending moment as front of leaf pushes up upon acceleration with a bending moment provided by the front mass of the car, ie engine, etc, are they just straightening out the force path thru 4 right? angle turns from the front hanger to the doorsills back to the TB crossmember, etc?.

If we knew what they are resisting, it would be a lot easier to design a solution. I suspect they are doing all the above, but some more then others, but which one? Say if twist was the main force, a large dia tube would be first choice, if bending moment, a tall I beam, yaw? bending, an I beam on its side, etc. My understanding is it needs to be the smallest and lightest shape/size that gets the job done. Anyone can oversize a solution, only a smart designer knows just how much is needed, if you way oversize, you look.....?

Years back member AAR? (patent attorney) had a lengthly thread on Subframe connectors, and main conclusion was the larger the crossection of the subframe, the stiffer, wall thickness provides a lot less stiffness then crossection increase gives. The installation advantages are numerous with the contour cut-out connectors, and installation ease IMO is thier only advantage. Performance wise, compared to a full tube they leave a lot on the table.

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