Those air bag upper mounts have a reasonably good moment on the frame rail without having a crossmember to tie the two sides together. Might twist and flex the frame leading to trouble eventually.
I added air bags to my 2 ton but put them between frame and axle so no twisting force on the frame.
The original type leaf overload spring pads on the frame mount closer to the cross members so better able to resist that twist, and they may take the load closer to the frame than the modern air bag shown, so less torque on the frame rail if so. And, the leaf springs if holding the same load apply that force to the frame at two places, so half the point load of the air bag.
Last edited by Grigg; 08/19/2019 10:23 PM. Reason: more info
