I have been using the Andersen hitch (pulling a 251 RK K-Z Spree trailer) all this summer and have about 12,000 miles on it. It has, from time to time, worked fairly well but there have been numerous issues. My "silent" hitch squalls like an injured alleycay whenever I make a turn and it is embarrassing to pull into a service station. Polishing the shank on the ball helped for a bit but the problem returned. There just seems to be a little too much stiction. I am considering a dry lube but I don't want a lube which works too well or the anti-sway friction will be compromised. I have broken clevis's three times (possibly because they are all examples of China's finest) and finally bored out the holes in the plate so I could upsize.
The saddle brackets ended up pointing upward and not aligned with the plate. This resulted in wear in the square tube. I built braces for the brackets and managed to cure this.
One can run them without grease but, since there is still movement of the ball in the tongue, I think grease is still a good idea.
I don't think there is sufficient travel built in to the polymer bushing to handle much in the way of dips in the roadway. I think a stack of Bellville washers, in conjunction with the bushings, might work better or even a coil spring, also in conjunction with the bushing.
I'm not sure if I will keep working with the Andersen hitch design or not but, so far, I'm not real impressed. GD
