My relentless pursuit to cure trailer sway - the dancing TT

Does anyone have a PP or HA in Northern California (Or North Bay) that wouldn't mind me trying one of these?



Just wondering...

Oh... So the truck has a "leveling kit" and it does not sit level. The truck sits high in the front. This kit (spacer) has been on the truck since I bought.




Ok, so I went to the scale at the feed mill. It was nice; no cost as long as I didn't what a certified tag. So I made a few passes at it.

Also, with the weight bars: I have to hitch up, lift the truck up about 3 inches, and then I can have three links loose, but it is still a lot to crank them up. Maybe, 1500lb bars would be better(?).

Here is a quick and dirty spreadsheet.


Digest on this.


I had a few friends over and measured the axles alignment and such. It was slightly inconclusive. It seemed that the two axles are a 1/4" out of parallel, but it was suggested that I hook it up and pull it through a level parking lot and retake the measurements.

Thanks,
Joe Zeppe

Is it just friction sway control being used? Are you cranking that thing real tight?

RCMAN46 wrote:
"While there has been some very good advice here, I think too often we tend to think of weight first. "



That is because most trailer sway problems are from low tongue/pin weights.

Very easy and cheap to check the tongue weight percentage. That includes all weights both axles on truck and trailer axles.

This has to be done as has been described multiple times in this post.

Need weights both with and without WD bars engaged.

If the last picture I saw of truck hitched was with the WD bars engaged you do not have heavy enough bars as the front of the truck appears to be badly unloaded.

We need tongue weight percentage so tongue weight alone does not tell us anything. We also need the total weight of the trailer.

Without knowing the tongue weight percentage you may be wasting money and time looking for other cures that may do nothing to correct the core problem.

From your pictures it definitely seems like your wd hitch is not transferring enough weight to the front. If I saw my truck way up in the front like that I wouldn't even pull out of my driveway. There are many links on this forum on how to weigh and many on how to interpret those weights. Before you do anything else go to the "Technical Resources-Towing"forum and read and follow the sticky "Travel Trailer Hitch Set-up Procedure" by BarneyS. I originally had major sway control problems with the same set up you have until I followed that post which cured most problems. I then installed a Reese Dual Cam Strait Line hitch and solved all sway. I often don't even feel the push from a passing semi. Even cross winds cause little concern.

I'd go for a sway drive as hooked up, then immediately try another truck on the same trailer using the same hitch apparatus leveled and weight distributed properly, over the same road as the first sway drive....

A Dodge with it's solid axels is so much better for off-road than any other pickup. To get the same real ground clearance, independent front suspension unit needs an additional 4 to 5" of lift. But a lift kit on a Dodge screws around with that brilliant front end geometry. There is good reason why lifted Jeeps drive in the slow lane.GM tried to do a 5-link front end, but gave up and just did 90 o track arms.

A simple and cheap fix, for weight transfer, is add-a-leaf. In your case the trailer, while they are there, get brass bushing and grease nipples. And do some measurements, the hangers on trailer frames are not noted for being accurately placed. If your trailer axels are over the spring don't be tempted to lift and go under with all your problems.

I haven't seen any else suggest this unless I missed it, but how tight are your friction sway bars? You might want to try tightening them up a bit I know when I first started towing I had what sounds like pretty much the same problem although my second sway bar pretty well cured it once I got the friction adjusted right, anyway I started trying them tighter until I got too tight you can tell because the trailer won't want to immediately straighten out after a turn. Then I just slowly loosened them up a bit until the trailer tracked right around corners afterwards the final thing was playing with the tire pressure. I finally settled on 45lbs. and now I can't feel most semi's pass unless they're the old broad noses ones traveling considerably faster than I am. And even then the push pull feeling is still not severe. Good luck I know this is maddening and dangerous but maybe one of us will hit on the right formula to help you.

You said you've pulled other trailers that weigh as much as this one and more. With this truck? I assume so. If that is the case it points to the trailer, hitch set up or weight distribution.

You said you had put 3 sets of tires on the truck. Which tires were on it when it pulled trailers of this size and larger with no problem? In my opinion you need a load range E tire for your trailer. And yes, I've owned the Toyo tires and got rid of them as well but that doesn't mean all E tires are the same.

It appears your truck may be lifted; is it? If so, what kind of lift? If blocks were used in the rear instead of replacing the springs the U bolts may have come loose.

What kind of hitch do you have? I couldn't tell much about it in the pic I pulled. If you have the type that is primarily a WD hitch with the external, bolt on, sway controls - get a different kind. They've never worked well for me.

Trailer tires: are they rated for the trailer? Are they set at recommended psi?

If it's trailer specific you probably need to have your axles/wheels/tires aligned/balanced (if it's not weight distribution). I've had one instance of an axle being misaligned and it did sway, but the sway was rythmic. It swayed faster the faster I drove as it pulled itself to the side then hopped back. If you've put enough miles on it you should see some sort of irregular wear on one or more of your tires. Out of balance tires can cause you grief as well.

When you go to the scales get the following.

Both truck axles without the trailer.

All axles both truck and trailer without the WD active.

All axles both truck and trailer with WD active.

Load trailer and truck as if you were ready for a trip.

You need each axle in each case.

sourdough2224 wrote:
There have been lots of thoughts and suggestions on this. The criteria posted by the OP gives me some red flags:

> 35" tires with 45-50 psi? That's a non starter for me. What is the rim size? What is the width? If your tires are 35/12.50 like I think I read you have to have wheels that are no less than 8-9", preferably 10 or your sidewalls are going to flex an inch or two to the side every time that trailer pushes them. You should have LT tires that would run about 80 psi; not 45-50. With that low of a pressure on tall tires you can't help but sway.

>Air bags at 8 - 15 psi. What brand of air bag? What are its specs? I just traded my 2012 pickup with AirLift 1000 air bags. Recommended pressure for towing was 35psi.

>I see a WD hitch listed. Nothing about any kind of sway bar or sway control. I would recommend a hitch with built in sway control. I have an equalizer and love it. Either way you have to have some sort of supplemental sway control with 35" tires.

>Your tongue weight is already 1300 lbs. You don't need any more. What kind of receiver do you have on your truck? What kind of weight will it support? 1300 lbs is about max for a 9000 lb trailer and I don't know that you need to be at the max. I do know you need a HD receiver when you get to those kinds of hitch weight.

These are simple things and things that appear to me to be obvious reasons for sway. With the numbers you posted I would not think about taking off in your truck pulling a 9000+ lb. trailer.

Fix the things I listed and I think you will see a significant reduction in sway and then you can move on to fine tune things.

I think this post has a lot of common questions and comments.
Ok, I'll start at the top.
>>The tires are D rated - 3195lbs tire rating @ 50PSI. This it the third set of these tires I've had on this truck with 137k miles & they are a LT tire. I tried Toyo Open Country ATs of similar size, and they are E rated with the same load rating, and a higher PSI... They were terrible and I took them off after a 1000 miles, 800 mile camping trip at 50mph. Worst trip ever. The rims are H2 Hummer wheels manufactured for the tire I have on them. The tires are the stock size for the H2. The wheels have been manufactured in widths from 9" to 10" wide. I do not know what one I have. The tires are rated for 8" to 11" wide rim.

>>I have the firestone "ride-rite" air bags. You only need as much air as required to level/support the load... The truck can handle the weight, but the bags are there to help. Force due to two air bags that are 6" diameter at 15psi: F = 2x(PSI)x(Area) = 2x(15psi)x(3.14*3^2) = 848 pounds of force. As you increase the pressure the spring rate increases and can become a harsh ride. Additionally as the leaf springs compress, the spring rate increases. I added enough air in the bags to raise the ball within 1 inch of ride height. >>>> So if we used 35psi Force = 1979 pounds of force! The truck would ride higher with the trailer than normal ride height, and ride really crappy. I am assuming on the diameter of your bags, because if you lower the diameter, the force decreases.

>>I do have sway control on the hitch. From my last set of photos you can see one of the friction type sway control bars, and I have two…

>>The Hitch receiver is rated low. Dodge really Fu(ked this one up. It is rated for 1,000 pounds of tongue and 10,000 pound towing… That being said: the trailer does not have that much tongue weight normally. As I said earlier, I removed weight off the rear and added a bunch of weight from my tool boxes on the truck to the front bedroom floor. I did this to artificially add weight, like everyone said I needed, to the front of the trailer. I didn’t bring a scale with me on my camping trip so it was a gamble to what I was adding. The WDH is rated 1,400/14,000 lbs. I would like to upgrade the stock receiver to a Class 5 soon.

>> I see your points, but I haven’t had these problems towing other trailers with the same weight, or more.

Downwindtracker2 wrote:
While I not an engineer , one of the components of sway is weight transfer, this could be from tire sidewall flex, or soft springs.

I've been driving Jeeps and now a Dodge truck, but a front solid axel will not steer on the highway as well as an independent. As brilliant as the geometry is. So the OP was wise to fix the front end.

>>It’s what I went to school for… I think the dodge front end and the aftermarket industry has a lot to be desired without spending another truck worth in parts. I have upgraded parts from Don Thuren fabrication, Carli, and Dodge upgraded parts. (truth from a dodge owner: they are far from perfect)

wtilley51 wrote:
When I set my TV and TT up several years ago, I was given professional advice which worked out great and continues to. With the TV empty, measure the TV height to the top of the front and rear wheel wells and note the difference. The goal of proper WD is to maintain that relationship when hooked to the TT and ready to roll. Maintaining the front-to-back relationship is key to ensuring sufficient weight on the front axle for proper control. The overall height of the TV may be lower which hitched but the F-R relationship is the important factor. In your posted picture, the rear of your TV is much lower that the front. This suggests too much load in the rear of the TV and/or not enough WD tension. Also, 1200 lbs of tongue weight is quite substantial for a TT of that size. I should think something more on the order of 700-1000 would be more appropriate.The unloading of the front axle in this scenario may well exacerbate your sway problem. You must also strive to get the TT as level as possible at the same time.

>>I have tried multiple hitch heights and ended with this one on the last trip because I was trying to keep the ball at the ride height with the trailer on and loaded, and the air bags inflated more, with less WDH bar. I did not move it back up yet, so the trailer is nose low, but my truck in this photo is only sitting an inch lower in the rear, and there is NO change in height in the front. My truck runs nose high unloaded. I was always taught to make sure the bars keep the front from raising, and shoot for .75 inch low in the rear ( +/- .5 inch). I too agree that 1,200 pounds is a lot. It was added to test a theory, and not normal for this trailer. In all I agree that it needs to be set differently, but also remember that I have way more weight in this picture than it was set up for when I left the house.

Turtle n Peeps wrote:

Harvard wrote:

Turtle n Peeps wrote:
3,4,5 and 6 have NOTHING to do with "causing" trailer sway.

Add more tongue weight. Your going in the correct direction, you just need to go more.

Correct, truck caster will not cause trailer sway BUT truck caster may play a big role in the overall corrective action required to trailer sway. IMO, without sufficient truck caster, the required corrective action would be required by the driver and the driver is usually 180 degrees out of phase to the required reaction. Again, IMO, having sufficient caster will dynamically/automatically dampen the systems response to sway long before the driver even notices the problem is starting. IMO.

What I am suggesting is a "lateral" porpoising, which is more commonly accepted as vertical porpoising in aviation circles.

Pilot Induced Porpoising

The OP needs to fix the root problem.

The root problem is sway (according to him) and that needs to be fixed. The TV has nothing to do with trailer sway. He could tow his trailer with a class 8 Kenworth or a Toyota T100 and he would still have trailer sway. He could put his trailer on a bumper ball or hang his trailer on a Hensley and he will still have sway.

He could tow his trailer with 1 degree of castor or 25 degrees of castor in his truck and it would not make any difference. He is STILL going to have sway.

If someone's air plane engine is burning oil are you going to recommend putting heavier weight oil in the engine or tear the engine down and fix it properly?

TV- tires, castor, hitch or anything else on the TV is not causing the OP's sway problem.

I'm recommending to fix the root cause of the OP's sway problem and not put some bandaid on his problem.

>>The Truck is better than ever, but I think that the TV does still have improvements necessary, but the root of the problem is the trailer.

Harvard wrote:
Joe, I am looking for a guinea pig to test my theory of approximately measuring front end caster from digital pictures. :B

Caster from Digital Pictures

If you will take the pictures (and post) I will do the interpolation. :) Note how the camera lens is in line with the outside side of the wheels AND the camera is orientated parallel to the ground/rv (not necessarily level but that would give better estimation).

This is not intended to be an exact science but we should be able to see if you have a caster problem "worthy" of further investigation.

>> I’ll Play, in your other thread though, after this weekend.



I have to come home early on Wednesday to go to the dentist (Broke a tooth while biting into a hamburger with a piece of bone in the meat). I plan on getting the truck and trailer in the current configuration over to the feed mill.
I plan on weighing the front axle, the loaded truck (still hooked up), the whole rig, just the trailer, and then I want to unload the weights in the front bedroom floor and get a weight of the trailer in traveling form without water. We’ll see if the scale house will play.


Keep it coming!
Thanks,
Joe Zeppe