Twitchy steering with a big travel trailer (rear sway bar help?)

[Grit dog]

With the shackle drop on the rear springs, this rear end squats like crazy with the trailer attached. Without the airbags aired up, the tongue weight drops 100 pounds.

Once the bags are aired north of 50 psi and the weight distribution hitch is setup, it’s displaying 3k worth of weight tension post adjustment.

I’ll admit Ive never used a weight safe hitch with the gauge on it. So I have no idea how it would calculate what you’re seeing. Although 3klbs sounds ridiculously high. Whatever that number means.
Your being lowered does not appreciably change the spring rate.
And 50psi in a set of typical bags is providing about 2800lbs of uplift. Which even accounting for the moment arm from axle to hitch is lifting more than the trailer tongue weight plus you’re removing weight from the rear axle with the wdh. None of this computes to being a good setup. At least from what I know.
I’m going to surmise some or much of the twitchy steering may be from improper trailer setup. You have taken the spring out of the rear suspension and then effectively also removed some rear axle weight. And could be transferring excessive weight to the front axle.
Figure out if you’re overloading your tires.
Then look at your air and wdh setup.
And don’t get wrapped around the wdh and sway control. That trailer should tow fine without any of that save for a good suspension and an adequately rated receiver. Until you try different setups I think it will be hard to pinpoint. IE doing the same thing repeatedly and hoping for different results.
Good news is you’re not seeing trailer sway. Which you shouldn’t even without the sway control but less so by locking it down with sway control.

And can’t judge by towing in the wind. If you have any substantial cross wind with your size trailer and smallish lightweight older truck (compared to a newer crew cab) and not getting tossed around bad then you don’t have much issue.
Lastly, “towing aides” like you’re using are frequently unnecessary and more of a sales pitch from dealers to boost profits than they are needed. I laugh everytime I see someone towing a trailer like yours behind a newer HD truck with all the gadgets and gizmos when dropping er on the hitch ball and hitting the road is all that is needed.

 

[bucket]

I’ll admit Ive never used a weight safe hitch with the gauge on it. So I have no idea how it would calculate what you’re seeing. Although 3klbs sounds ridiculously high. Whatever that number means.
Your being lowered does not appreciably change the spring rate.
And 50psi in a set of typical bags is providing about 2800lbs of uplift. Which even accounting for the moment arm from axle to hitch is lifting more than the trailer tongue weight plus you’re removing weight from the rear axle with the wdh. None of this computes to being a good setup. At least from what I know.
I’m going to surmise some or much of the twitchy steering may be from improper trailer setup. You have taken the spring out of the rear suspension and then effectively also removed some rear axle weight. And could be transferring excessive weight to the front axle.
Figure out if you’re overloading your tires.
Then look at your air and wdh setup.
And don’t get wrapped around the wdh and sway control. That trailer should tow fine without any of that save for a good suspension and an adequately rated receiver. Until you try different setups I think it will be hard to pinpoint. IE doing the same thing repeatedly and hoping for different results.
Good news is you’re not seeing trailer sway. Which you shouldn’t even without the sway control but less so by locking it down with sway control.

And can’t judge by towing in the wind. If you have any substantial cross wind with your size trailer and smallish lightweight older truck (compared to a newer crew cab) and not getting tossed around bad then you don’t have much issue.
Lastly, “towing aides” like you’re using are frequently unnecessary and more of a sales pitch from dealers to boost profits than they are needed. I laugh everytime I see someone towing a trailer like yours behind a newer HD truck with all the gadgets and gizmos when dropping er on the hitch ball and hitting the road is all that is needed.

I 100% agree about the towing aids. That stuff is useful on lighter vehicles or vehicles that are way under-sprung for towing. Like modern, cushy riding F150s and Escalades where a 5k trailer will put the thing on it's bump stops. Or old station wagons pulling canned ham.

 

[carnutjw]

I've been watching this thread since it started, kinda letting it "air out" before I chimed in. My Suburban is a 1987 R20, 8600gvwr, towing a 21' camper weighing in at 3900-ish lbs. dry weight. Where I live it is the windiest mid-day, the time of course when we prefer to be towing . I don't have a lot of experience towing, but I'm surprised how poorly my Suburban handles with the camper in tow. I don't feel like my life is in danger, but I thought it would be more stable. I have a Fastway E2 round bar hitch (WD and sway control) that came with the camper when we bought it. My tires are 265/75-16 E1 rated all terrains on 16x8 wheels.
Back to the one of the OP questions: has anyone adapted a Hellwig, Addco, or any other sway bar to a 14bolt full floater rear end in a Suburban? There are far more options for the half tons, and I assume with some bracket and U-bolt mods they could work on a 3/4 ton.

 

[DoubleDingo]

Towing in the wind will make anything drive/steer squirrely, look at big rigs that get overturned in high winds. I haven't towed in high winds but have driven in high winds 100s, if not 1000s of times, and every single time there are big rigs either on their side or parked so they don't end up that way. Or they get blown into an adjacent lane and fight every inch of their forward movement to stay straight as they snake left and right down the road, and there's the trucks with campers leaning way over, etc. I've also seen motorcycles in high wind scenarios and they are usually leaning at 30 to 45 degrees to maintain a straight line.

I would not recommend a rear sway bar, and if you do install one it has to be smaller diameter and more flexible than than the front one, or the rear wheel will lift causing traction issues. You want all four planted as firmly as possible.

 

[Bennyt]

I'm staying out of the steering, tire, twitch discussion as I don't believe a sway bar would address the issue at all.

But I have added rear sway bars on a few trucks and definitely helped in wind especially when equipped with camper shells. Our HHR SS was horrible in the wind; added a small rear bar and it was night and day on windy days.

 

[TotalyHucked]

Yeah windy days will make even the most perfectly set up setup squirrely. I've got thousands on thousands of miles towing - open/flat deck/enclosed/gooseneck car trailers, landscaping trailers, U-hauls, various other box trailers, etc and the wind will make any of them a wild ride at times.