[Bob p]

Interesting discussion. The reality is that once a trailer is hooked up, it all becomes a rig - with an entirely new set of parameters in play. Total weight and weight distribution, stopping distance, tail swing or tail drag, tongue weight and hitch weight (and related load specs). Probably I left out something, but y'all get the idea.

On the big rigs I drove weight per axle was established by proper loading of the cargo on or in the trailer, and by sliding the trailer tandems. With a nod to @Clint 's point about getting on a scale, even one notch on the tandems would make a difference in how it weighed out on a scale.

Which leads me to note that if one is driving while improperly loaded in certain states, DOT will ticket the driver for the improperly loaded vehicle. Why is that?

In one word, safety.

My wife and I just bought a travel trailer so I'm going to school on the weight distribution hitch and other nuances to assure what I do passes at the scales, and does not overstress any part of the combined rig. I probably don't need airbags or Sumo's, but might add one or the other just to assure myself I've covered all the aspects of the chore.

Best to all for a great week.

I use the WDH with my TT plus I added the Sumo’s just so I didn’t have to tighten the load equalizer bars as much. As anyone who has put a load in the bed, the trucks springs are designed for a comfortable ride. The SUMOS make the truck a little stiffer but also act like an anti sway bar is installed, it no longer sways to the outside on a fast curve. Before when I hitched the travel trailer (540 lb hitch weight) the rear of the truck would go down 4“, with the SUMOS it only drops 2”, and the front rises 1 1/2“(measured with a tape measure from the top of the fender well to the ground. Before I would “drop” 7 links in the chains, now I “drop” 4 links.

If actually using/working your truck = truck tasks...just know the factory leaf springs are your weakest link. Match & install aftermarket leaf springs to fit your intended purposes.

I don't tow, so no WDH:
I have airbags and aftermarket medium duty leaf springs installed in the same order, but a few years apart. Had I first installed the medium duty leaf springs, I don't think I would need the airbags...but they're there should they ever be needed.

SUMO springs much cheaper and support the
load the truck can legally carry, 500 lbs. each side.

 

[shift_RUSH]

The factory springs will sag and eventually need replacing. There's not much else to say about this fact. Or is there?

I was told airbags would prolong the life of factory leaf springs = not true. Heavier duty leaf springs matched to one's needs to the rescue.

Do SUMOs prolong the life of factory leaf springs? I certainly see their advantage in always being there for the assist when loaded up.

What will or won't work w/ a WDH. I seem to recall that airbags won't.

 

[Bravo13]

If your truck has a proper setup WD hitch there is no way you should need airbags, if you do you have too much hitch weight.
Airbags are great for when your bed in loaded and not towing.