Interesting input. Thanks!
I am almost sure they aren't galvanized leaf springs given how fast they corroded. I thought they were painted, but if so it obviously didn't work very well.
I'll dig around the inner-net for galvanized leaf springs as well as that torsion bar.
My ony question regarding that torsion bar is how to detect it is nearing the end of its service life. I, for one, am not a big fan of catastrophic failures on interstate highways?
I don't believe they fail catastrophically. The interior tubing is large enough that it can't rotate inside the exterior tubing. The triangle shaped rubber pieces just provide cushion between the two and last a very long time. I'm nearly certain that the failure mode is that your trailer ride starts bottoming out steel on steel as the rubber deteriorates - but they have a reputation of lasting for a very long time.
