I just picked up a set of used Metco rear lower control arms. The SOB's are heavy!!! I highly doubt that solid bar stock is required, so anybody ever thought of drilling some holes, or milling the bars down? I have been considering milling a groove in the sides of the bars between the front bushing to about 1.5" in front of the front swaybar mount hole. Should take 1-2 #'s out of them, if not more, gotta do the calculations, and will as soon as I can remember what the density of Al is...
I have read that some of the BMR arms have been failing. I have to assume that it is a result of the stiff bushings as well as the stiff rear bars. I am not sure I would blame the material, there is a lot more stress going on here than stock. With the urethane bushings there is little to no give, and I wonder if this causes frame issues as well. Add that to stiff geometry of a tubular bar and you have stress risers. The stock arms would easily twist, and the stock busings had a lot more compliance, so stress was more distributed, and more than likely lower as well.
During development of other body on frame vehicles, I have seen bars cause frame bending (i/e the frame was less stiff than the sway bars).. I wonder what these stiff bars and control arms do to our frames?
I think GW has the best idea with the spherical joint on the front of their arms, as this reduces bind in the suspension.
I think it might be time to develop a frame mounted bar. Looking at way the sway bars mount on our cars is not the most efficient way of controlling body roll, I bet a frame mounted bar would not need to be nearly as stiff to provide similar roll resistance... However, moving the swaybar off the control arms will also eliminate the swaybars contribution to lateral location of the axle. I know the uppers do most of it, but if you consider the stiffness of even the stock bar, it is hard to say that it does not contribute.