Aside from all the bickering, and finger pointing, I found this thread useful. First and foremost, trust but verify comes to mind with dealers. I have dealt with Ford on several occasions, and trust me, mechanics are nothing more than paid wrench jockeys now. Very few of the new breed know how to troubleshoot without the great cloud computer telling them where to go. The same holds true for RV dealers. They are assemblers, they basically pull the pieces out of the box and bolt them together, regardless of if they are done correctly or not. It is up to us to verify they did it correctly.
I ran into the same issue with my trailer when I first towed it home. I was under the assumption the dealer knew what they were doing and knew what the trailers weight was since that is their job, to sell and hookup trailers. I was wrong. My drive home was a handful and I thought "what the hell did I get into" and found out after getting it home, and reviewing all the dealer did, then getting the manual out for my 10+ year old hitch, that the guy who hooked it up was an idiot. The ball was too high, so there was NO weight on the bars. After taking it all apart, taking all the measurements and putting it all back together correctly, now it works perfectly. Its an old Husky round bar system that pulls my Coleman 274BH just fine. I added a single friction sway bar to it and sway is no longer an issue, no more porpoising, just nice level towing. When a cross wind hits, the entire rig moves, and I doubt that either of the two mentioned systems would prevent that.
At first I thought I had to wrong bars and almost made the mistake of purchasing heavier bars for my hitch, and had I done so, it would have had a negative effect. What I did was buy a cheap $9 bathroom scale from wallyworld, cut a couple foot long pieces of copper pipe, and screwed two 7' long 2 x 4's together and weighed my loaded trailers tongue, and found it fell well under the weight of my existing bars. In my case I had the correct hitch, it was just incorrectly setup. In the OP's case, not only was it incorrectly setup, it had the wrong bars. What I find disturbing is that the RV dealer doesn't have a tongue scale. You would think it would be a standard tool in their inventory considering they sell hitches and would need to know the actual tongue weight in order to sell the proper hitch.
What everyone can take away from this thread, know the tongue weight, and make darn sure the installer did the job properly. Two things I did, I took a regular construction level and placed it on the floor of the trailer and leveled it, then installed bubble levels on the side and front. Then I was able to get the proper measurements for the tongue height. I also made a simple tongue scale to get the actual weight.
So when a n00b (or anyone for that matter) goes in to get a hitch installed, make sure the dealer does A). level the trailer and B). weighs the tongue. If they don't do both, seek another installer. If the OP's dealer had done those two items, he would have been a happy camper, no pun intended.
