Mine tows tows almost 38 feet just fine with bags and 10 ply tires. I've done a lot of research into the ratings. All ratings are gauged with the factory crap tires. They aren't rated with any of the real factors that come into play later on such as bags or better tires. If you want to know more about it, find guys who haul for a living or who've been doing it for decades. My truck has done a great job of hauling my TT. The last 2 things I plan to do are install a Helwig anti-sway bar and swap out the 3.21 to a 4.10.
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An Equalizer hitch makes all the difference with sway as well. Solid bars. No chains. It's like night and day.
See, I can't stand those 'anti-sway and WD all in one' hitches. I'll never buy one, because your anti-sway is DIRECTLY connected to the amount of weight you're trying to distribute. In other words, a heavier trailer will inherently have more resistance to sway than a lighter trailer. It also means that a trailer you pulled with a half-ton with no sway but lots of squat will have less squat but more sway with a 2500 or 3500.
Now, if you go with a standard WD hitch and add the separate sway control bar, you can adjust your sway and your WD independent of each other. Need more WD? Move a link on the chain. Need less? Move a link on the chain. Need more sway control? Tighten the lever. Less? Loosen it.
In engineer-speak, that's called 'decoupling' parts of the system. When your parts are dependent on one another, a small change in one creates a change in another. When they're decoupled or independent, a change in one should have no effect on any other part of the system.