I've been a forum member for a couple years, don't post much though. I have been reading through as many threads as I can and haven't seen anything that really answers the question of how to fix the trailer sway. The Excursion is currently for sale on craigslist, but I hate to see her go so I want to see what fixes this group may have.

Ex - 2004, v10, 4x4, 143,000 miles. Timbren helper springs front (probably coming off) and rear. No rear sway. Load range E aired to 60fr 80 rear. Tires are only a year old.

Trailer - 34' Loft (13'1" tall). Use an equal-i-zer 4-point WD hitch with anti-sway. Weighs 8,300 to 9,000lbs depending on the particulars of the trip. TW is around 900-1000lbs (again depends on what the trip has is store).

I guess the real question that I have is how much difference does the rear sway bar make? I towed the trailer just short of 1,000 miles last weekend with my 1/2 Silverado and it did not exhibit anywhere near the sway I get with the Ex. Of course the mpg is the same so with the 26 gallons of gas available to the Chevy I barely leave one gas station before I have to stop at the next and the kids don't stay nearly as quite. Any suggestions on getting this under control are very appreciated. We have a 2,300 mile tow coming up at the end of May to kick off a couple months of camping and I would sure like to be able to have the big brute with us.

 

I put in a sway bar before I started towing our TT 28ft. I also added airbags and run 25 psi. I don't have sway issues. Off course the weight distribution hitch with friction sway is there too.

 

We have a Hensley Arrow and have never experienced sway. I am assuming you don't overload the rear of the trailer. We did add a rear sway bar and while towing it didn't seem to make much difference (probably because of the Hensley).

 

Your tongue weight is on the low end. If I had to guess the trailer sits a little more nose down on the chevy.

 

The tongue weight is a good point, I'll try filling the water tank and see what that does. If it ever stops raining here I am going to crawl underneath to make sure there is not something else going on. The trailer is just about level on both, but the WD is slightly less when attached to the Ex because I have to adjust the ball up a couple inches. I guess I'll try the sway bar just to give the Ex a fighting chance. Just hate to spend that money and not have it work.

 

And I just noticed that I'm running the same tires as StreamOn so I can rule those out.

 

Same thing, have a Hensley Arrow, no sway whatsoever. Drive it with one hand going down the road, no stress, worries, nothing. Best thing I ever bought for towing.

This is a 37' long TT with a 34' box, 11'5' high.

If you have a backup camera, hookups take 30 seconds.

Find a used one on CL for under 1000

Also your tongue weight is too low, shoot for 1200 lbs.

 

I tow an brick in the form of a v-nose travel trailer right in that weight neighborhood, and I have very little to no sway at all. In fact, if you rather tow it with a half ton chevy, then something is really wrong with your rig. I can't imagine that would be a comfortable ride at all, nor would the truck and especially the transmission, last very long. Isn't that at the very upper limit or even over rated capacity?

Mine has:
- V/mod B springs (got lucky and scored take-offs on craigslist)
- Hellwig adjustable rear sway bar on the stiffest setting
- Bilstein shocks (not even the best ones; I think they are 5100 series)
- properly set up WD hitch with 1,000 lb bars (I think so anyway based on results; I intend to verify as soon as I get a few more things sorted with both truck and trailer)
- friction bar anti-sway control

I usually tow at around 60 or 65, but I've hit 75 going downhill to build up a head of steam for the other side of a valley. It feels completely stable at all speeds. The whole thing shimmies a little bit when a big rig passes me, but I don't think there's a way around that. You feel it in motorhomes too and it's not like they can sway without a trailer.

I really couldn't be happier with the way it tows to be honest. I would recommend this configuration to anyone.

I do have to crank down pretty hard on the friction bar though. If it's not quite tight enough I can feel it sway a little.

 

I'll echo the tongue weight issue. You should have a good 13% of the trailer weight on the tongue, and 15% is perfectly acceptable (assuming your equipment is rated for the actual weight).

 

I'm another Hensley Arrow user, so no sway at all here either, TT is 41' hitch to bumper 11,000lbs with 1400+ lbs of TW.
Are your weight from actually scaling the rig/trailer? I agree that that listed TW is too low and your mention of not as much WD with the EX doesn't sound right. Are you positive that the hitch is setup correctly? If I'm not mistaken your hitch increases it's sway control friction as more tension is applied to the spring bars, so if not applying much WD you are coming up short on sway control.
Too low of TW will lead to trailer sway especially with a long and tall trailer. What are your WD spring bars rated at?
You are running more pressure in the EX's rear tires than needed if you are at or below the rear axel's rating. Too much pressure can make things get a little squirrelly, just like not enough pressure.
Just to be perfectly clear, are you getting too much movement on the rear of the EX or is it truly trailer sway where the TT is wagging back and forth at speed? If its trailer sway does it do it on it own or only when influenced by outside forces like semis passing or crosswinds? Do the sway oscillations continue to build until it gets scary and out of control or does it find a frequency and then stays there? Does slowing or speeding up affect the sway? Will a quick jab of the trailer brakes via the manual lever on the TBC stop the sway?
What trailer tires are you running? Type (ST, LT or P), size, load range, age and pressure. And if you have a scale ticket(s) can you provide the steer, drive and trailer axle weights along with the EX's unloaded weights? Is this "loft" TT a Destination or park model, it seems very tall?
I know that you are getting hit with a ton of suggestions and questions here, take you time and try to answer them all as best as you can and let it all overwhelm you. We know that the EX can be a great tow rig, it just sometimes needs a little tweaking to get it there.

 

I will answer as best I can. It is true trailer sway with the back of the trailer wagging. The sway builds until I manually apply the trailer brakes. Crosswinds make it more frequent but sometimes is just starts out of no where, I would guess road imperfections. Semis seem to just push or suck, not illicit sway. I honestly don't know anything about trailer tires so until just now I didn't know their were different kinds. Tire age is new, PSI is the max on the sidewall. I think it is 65. I filled them, just don't remember what I filled them to. When the rain lets up I will head out and take a look. Scale ticket is the same story, out in the rain. It is not a destination or park model, just a unique TT floor plan with a loft.

You mention the PSI in the rear tire, what should it be? I have heard of a formula that can be used to figure out the correct PSI but I have never seen this formula documented anywhere.

 

Andym - The Chevy actually pulls the trailer great and the trans temp never got over 200 pulling through the hills of western Mass across to Buffalo. The fact that the half-ton even got a try out was because the trip was already planned for my son's birthday and I didn't feel safe taking the Excursion. I do hope to get the Ex dialed in because 6 people in a CC truck is a little tight for my liking. As far as the weights, yes it was right at the top of it's ratings. Had we been packed for more than just a week-end I am sure I would have been well over.

 

My first clue the problem is with your Ex and not the trailer setup is that somebody already installed Timbren springs in the front. This tells me that your front springs were shot and rather then replace them they threw a bandaid on it.

Question, How does the Ex handle with the trailer attached ?
Does it cruise rock steady in a straight line down the highway ?
Or
Does it take some effort to keep it between the lane lines ?

More clues can be found if you can provide.

1. Ride height,
measure all 4 corners, from the center of the wheel hub to the bottom of the fender arch.

2. Pictures of all 4 leaf springs so we can verify what is under your Ex. A pic of the shocks and bump stops would be helpful.

3. If you have a picture of your trailer hooked up and ready to travel that would be cool also. Ie. Is the frame of the trailer level ? Slightly nose high ? Sometimes it is as simple as hitch height.

 

The tires are ST aired to 65psi. Evidently my wife sent to the kids to clean the Ex out at some point. So I can't find the scale ticket, or my registration, insurance, or anything else that resembles trash to a kid.

 

Stock size tire the psi should be 55 in the rear, just like the placard on the door pillar says.

A 265/75r16 @55psi will support 2625 each, or 5250 pounds which is also your rear GAWR.

Load and inflation table
https://toyotires-1524598101.netdna-...s_20170203.pdf