Various trailer hitches have anti-sway as part of the design, like the Equalizer WD hitch.
And there are anti-sway add ons for some hitches.
On a tow vehicle while commonly called a rear "sway" bar the bar is really an anti-roll bar and doesn't do much for "sway" of the tow vehicle.
When I drove our Ex home the first time I could tell without looking there was no rear anti-roll bar.
It handled horrible in a turn, the rear rolled to one side, the front not so much.
The shocks were worn out, too.
A vehicle with a balanced set of heavy anti-roll bars will execute turns very controlled and nearly flat.
Having the tow vehicle under control will be very helpful controlling a trailer.
For towing our 27ft 7k TH I installed F250 rear springs, Hellwig front & rear anti-roll bars and new Bilstein shocks.
These upgrades were an amazing improvement in handling for the Ex.
The tongue weight on our trailer is 1050 lbs , 15%, and I never get any hint of trailer sway.

Does your 1/2 ton Silverado have a rear anti-roll bar?

 

Pirate, do you have one of your handy dandy tires pressure weight capacity charts to help answer the OP's tire pressure question?


EDIT: Lol, and the Pirate was posting the chart as I was asking about it!

 

Link and chart 4 post above

 

Pirate4x4 - I must tell the truth. The front springs are not shot. All my bump stops were shot or missing so I ordered the rear timbrens (knowing I was getting this larger trailer) and new front bump stops, but I screwed up and ordered front timbrens and new front bump stops. Figured I had them I may as well try them out.

Corners. I just measured the corners about a month ago, they all match the measurement I found on this forum somewhere. I will measure them again to make sure I didn't fudge it.

I will gets some pictures, probably be Sunday before the sun visits here again.

As far as how it handles, not good on the highway. On secondary road and to speeds up to about 50 it is fine. I'd even goes as far as to say great. Get on the interstate and somewhere between 50 and 65 it just gets loose.

 

Thanks for chart, I have never seen a chart like this. I appreciate everyone's input and help. I have a few things to try out when the weather clears. I have to put the little one to bed but I will keep you posted.

 

Timbren are good as long as you are not trying to "fix" sagged springs.

Your non towing symptoms sound pretty typical of sagged front springs and or not enough front caster. As has been said, if it isn't rock solid when not towing it is just going to be worse when towing, yours sounds worse.

A few more things that will help us hone in on likely culprits.

1. What shocks do you have and how old are they ?

2. Have you had the ball joints replaced or checked recently ?

3. Have you checked the steering box backlash and the tie rod ends ?

4. How many miles on the front wheel bearings ?

All fairly easy fixes and all can contribute to the poor handeling you describe.

 

It's like a Hensley Arrow convention in here.

 

I called those guys for a part and they are rude ****** so I hung up. I'd like to think this place is a tad more helpful. Anybody want a busted HA ? Lmao

 

I notice significant difference with my upgraded sway bar on as opposed to former EX stock bar. The former was good, but whatever the new one has is better. The trailer if loaded well should make a difference also. Weight over the axles and after that spread well throughout. Also your hitch point may be not be at the best height. Lots of YouTube videos explain this stuff well.

 

Which anti-roll bar are you referring to front or rear and what is "the new one"?
Most Exs came with no rear bar to compare to.
I think some late years, maybe only 2005, got a rear bar with a "tow package" option, but that was probably very few.
The Hellwig rear bar is a big improvement over the stock F250 bar and a huge improvement over none at all.
The Hellwig front bar is a nice improvement over stock and balances out overall cornering well.

 

I dont know what the rear is but the rear is what I am referring to on both. I thought the rear on my 03 was stock...perhaps not. Then on my 04 it is much heavier. I don't know what it would be?

 

Tried to PM you a question, but your box is full.

 

Cleared It.

 

I towed with and without a rear sway bar. Believe me it is a night and day difference when towing. Even when not towing it is a huge improvement. As far as tongue weight goes, you want 12% of the trailers loaded weight. That would put you around 1200 lbs. right now you're around 10% which is too low for the trailers weight you posted.

 

FWIW, despite the name, a "sway bar" has nothing to do with sway.

It's a torsion spring that resists body roll. It would be more appropriately named a "roll bar" but that name already has a home in our minds as belonging to a roll-over bar.
It can be confidence inspiring (read "it feels good") though because vehicle body roll feels uncomfortable and resisting that roll masks how much lateral load is being produced. It's important to know though that with body roll comes grip. Flattening it all out with heavy sway bars will make the vehicle feel great while it's sliding in to the ditch for lack of grip.

Sway is the trailer wagging behind you.

Make sure you have 10 percent of your gross trailer weight on the tongue.
Stay within the weight capacity of the trailer and its tires.
Stay within the GCWR of the vehicle plus trailer - this is the rule most people with sway problems ignore and wonder why the tail is wagging the dog.
A friction "sway control" device + weight distribution hitch will help a lot. The Hensley Arrow is popular with good reviews, I haven't used it. I have used the "Equal-i-zer" and it was excellent.

EDIT: HA! Morning fail for me, I see you have all that covered in your 1st post. My best guess then is that the trailer weight is multiplying the steering wander that Excursions are prone to having. I think rear sway bars are over-prescribed to problems they don't help with but in your case it might help. Is your Excursion lifted at all? That would be a better case for a rear sway bar due to the higher center of gravity. If you haven't I'd take a look at the usual suspects for general steering wander. 5 degrees of front caster works wonders, I have 7 degrees and no regrets.