Sway Fatigue

[Rough31]

I am wondering if there are parts of the tow vehicle/trailer that will suffer fatigue over a long haul trip resulting in increased trailer sway while you travel. And what can be done to reduce those problems.

My truck is a 2011 Silverado 1500 with the 5.3L engine and factory tow package. The vehicle is rated for 10,500lbs. My trailer is the Sunset Trail 31SS. The factory dry weight is 7000lbs so I am well within my vehicles tow capacity. My hitch is an Equalizer with 1000lb sway arms.

I recently completed a trip from Southern Ontario to Disney World and back again. On previous trips my set up has been very effective and I felt I had weight distribution and sway control very well balanced. I do not carry more then 5 gallons of fluids and am consistent from trip to trip with what weight I have on board and how it is carried.

In both directions, day one was completed without noticing any significant sway issues. Day two was generally still comfortable, some jet wash movement was noted but nothing significant. Day three, on both trips was white knuckle at times.

On the trip South, I did not unhitch at the overnight stops and I wondered if that may have resulted in some form of fatigue of the suspension or other parts. For the return trip I made sure i unhitched each night and still experienced the same challenges. I raised my L-brackets and that did seem to provide some relief but did not completely resolve the issues.

I tried to note when it was the worst. It seemed after any rest stop I would feel more sway for another 30-40 miles and would see a significant difference after refuelling which would be the only period of major weight change.

Any thoughts are appreciated.

[handye9]

Do scale weights with truck and trailer loaded for camping. Without actual weights, you (and we) are only guessing.

There are several things that can cause or contribute to trailer sway. Your problem could be any one, or a combination of them. Some, you can do nothing about, some you have already ruled out. Most common causes:

1. Trailer is too lite on the tongue

Tongue weight should be 10 - 15% of loaded trailer weight. Average is 12 - 13%.

2. Hitch not set up correctly

If hitch is not restoring enough weight to front axles of the truck, subconscious movement on steering wheel, oversteering, cross winds, or subtle changes in road surface, can cause sway. If hitch ball is set too high, trailer tows nose up and you have similar situation to lite tongue weight. In original post, OP stated 1000 lb bars on his WD hitch. If OP's estimate (8500 lb) for loaded trailer weight is correct, and, if he has an average tongue weight (12 - 13% = 1020 - 1105 lb), his bars could be undersized.

3. Unbalanced loading

4. Overloading or soft suspension

If you are close or over your payload, you could have tire sidewall flex or body roll on tow vehicle. Compare loaded weights to payload / GVWR of tow vehicle. With a long trailer hitched to a short / lite truck, you don't need much crosswind to affect stability.

5. Unbalanced or low tire pressure (either truck or trailer)

6. Insufficient sway control

7. Cross winds.

8. Bad roads.

9. Trailer axles out of alignment.

10. Bad trailer tires.

11. Bow wave from passing vehicles.

[Rough31]

What the OP understands... Is that I have experinenced on two specific occasions driving challenges that were not consistent with approximately 9000km of towing time. Something was different and I am attempting to figure out what might have changed on those two days that effected the vehicles performance. Could my set up require tweaking, of course it could, no hitch setup is going to be 100% perfect. That being said, I have followed the manufactures specs for setup and remeasured during this year to ensure I was still getting appropriate transfer from rear axel to front.

Could I benefit from knowing my weights, of course I could. But I do trust the certified weights I was provided by the dealer and am very cognizant of what I carry in my rig. A search of persons who have posted details of the Sunset 31SS tongue weight I have found results between 750 and 850 (Within 10-15%). I will be taking Turtles advice on how to check mine and expect it will exhibit similar results.

Fatigue was my term, because to the 99% of the populaton who are not engineers, It means tired and in need of rest. I admit to not being an engineer and wondered if parts such as my torsion bars, shocks or suspension could in fact simply be tired and in need of rest after 3 straight days of towing. Based on my driving history with the vehicle this is a fairly logical hypothesis, one which an engineer could probably confirm or deny for me.

And as for being ok when everything is NOT severe... My driving conditions were actually far more severe when it was driving well. When I experienced the most significant sway I was on a Pin straight section of highway in Georgia on a clear sunny day, travelling at approximately 65 MPH, a speed which I have been able to consistently tow at without challenge. If is had happened when things were severe... I would probably had a very different hypothesis.

[BenK]

The OP is on the hairy edge seems to not understand that, IMHO

Whether by sizing and/or setup

Comments on going out to actually weigh everything and doing the simple math
against their TV's ratings is towards finding out where the OP is in reference
to their TV's ratings

Orientation stuff is towards their setup (all of the dials, knobs, etc to
adjust towards a setup goal)

The goal on setup is to restore enough weight back onto the TV's front axle from
the TV's rear axle. It used to be 'even drop', but the various OEMs have such
different suspensions that the best advice is to follow the glove box manual
on how much to restore the TV's front axle to

The trailer tongue should be in the 12%-15% range and I prefer heavier. Why
folks have asked what the tongue weight is

The orientation of the trailers tongue should be level at it's highest pointing
I prefer slightly nose down and that has solved many folks problems with just
that

"Fatigued" to an engineer means it is failing to failed....AKA...busted

For the condition the OP describes...says they are the hairy edge of their
ratings and/or not setup properly

Meaning that they are okay when everything is NOT severe...but...when it does
move towards a severe condition...it sways for a 'white knuckle' experience...

[Rough31]

Turtle... Thanks for the link... I know where i will be this weekend, figuring out TW

8iron - It is a 2013, this was my first full year pulling this rig, I picked it up a year ago today.

Coyote - I did consider me just being overly sensitive, but on both of the travel days that I experienced problems my wife commented unsolicited on how much it was moving. For her to notice it with out the input of the steering wheel in her hands told me the movement was fairly significant. The road grease theory is interesting and certainly a possibility.

Anyone have thoughts on the trucks factory rubber and how that contributes to sway? I am actually looking at replacement tires now and considering brands built for heavier loads.

[Coyotecprs]

So if your weights in the trailer was not changing much like carrying water in the waste tanks to cause a change in sway then maybe your sway control was changing somewhat day to day. Possibly the weather was changing too. I think some of it might just be perceived changes like just after a rest stop. Maybe you are more sensitive to the moving after stopping for a little while but after a while of driving you notice it less. I know you are setting your tension bar the same each day but is it possible that road grease build up on the bars reducing it fiction enough so that sway control got worse.

[Turtle_n_Peeps]

If you don't have a measured tongue weight I can't help you. It's the first thing we need to diagnose sway.

If you have a bathroom scale you can get the tongue weight for us. Here is how to do it. We also need a total weight of your trailer but at least a TW will give us an idea of what we are dealing with.

[APT]

I would start at scaled weights. [urlhttp://catscale.com/cat-scale-locator]CAT offers a locator, but I'm not sure if they operate in Ontario. Otherwise, most landscape supply facilities have scales that might be worth calling. It will prove you are right about towing weight, but more importantly is the TW% and WDH loading which are the largest affects TT owners can change to affect handling. Most vehicles tow well with overloaded and as you said regardless the combo has proven better in the past.

Since you have logged many kilometers with the setup, there are other possibilities. The truck or TT alignment may be off. Potholes do wonders!

[8iron]

Setting aside the weight issues you may have with this combo, what year us your TT? Do you know what Lippert axles are under it? Any abnormal tire wear? Crossroads replaced quite a few axles in earlier Sunset Trails that were not up to the task that Lippert said they were. (This I know from experience). A bent axle could effect towing dynamics but I'm not sure why it would present itself only after 2 days of travel.

[Rough31]

Turtle... I have not measured the tongue weight. Not even sure there is anywhere near me with the capability of doing that.

TXIce... Sunset trails ships there trailers with a certified dry weight equipment included. Each unit is weighted on delivery and individually marked. I am going on memory because the rig is not at home but mine came in at 6982lbs.

When I bought the rig I assumed 1500lbs in cargo/people/stuff and wanted plenty of room to spare which was why I went shopping with a 7000lb limit. I have towed this set up this year with 6 grown men and a weekend of beer in the truck, easily outweighing my family trips by 1000lbs and had no issues at all.

I know my towing weights are the obvious easy answer to this issue. And if the sway problem was consistent I would suspect that was the correct answer. But reality is out of 9000km of travel the sway problems have only occured on two days and both times after three straight days of towing.

Truck length is an issue, the short box wheel base is going to struggle with a longer trailer, but again that does not account for the inconsistent performance. Tire pressure was checked prior to the trip on both vehicles and was in very good shape, as noted my only concern there was when we hit record temps inthe South that expansion may have over inflated the tires.

[TXiceman]

Rough31 wrote:


My truck is a 2011 Silverado 1500 with the 5.3L engine and factory tow package. The vehicle is rated for 10,500lbs. My trailer is the Sunset Trail 31SS. The factory dry weight is 7000lbs so I am well within my vehicles tow capacity. My hitch is an Equalizer with 1000lb sway arms.


Any thoughts are appreciated.

I doubt it the trailer weights anywhere close to the 7000# dry weight. Dry weight does not include any item listed as an option...A/C, microwave, awning, TV, batteries, etc. You add propane, some water and your supplies, it can easily reach 8000#.

Your truck 10,500# tow rating is a maximum, with a base model truck, no options, no cargo, no passengers other than a 150# driver and no hitch. For every pound you add to this base model, the 10,500# number is reduced by that amount. So load up the family, kids, dog, firewood and camping supplies and see where your truck weight falls relative to the GVWR. A 1/2 ton truck with a 8000# trailer will have a hitch weight of something like 900# as a minimum.

GVWR - loaded truck = Maximum hitch weight or payload capacity.

GCWR - loaded truck = Maximum loaded trailer weight.

Are you OK on both of these numbers...I doubt it.

Ken

[Turtle_n_Peeps]

What is the measured tongue weight of your trailer when fully loaded as above?

[Rough31]

Water was not a consideration... Only fluids I carry are about 5 gallons in my fresh tank for roadside emergencies, and i carry that consistently on purpose to not change my balance. My grey and black tanks were emptied each morning before travelling... Again to not change my balance,and because I am cheap and don't want to waste fuel hauling dishwater around the country 🙂

We don't take much gear with us, and what we do take is generally stored in the same position on all of our previously successful trips. The only place we might have been a little heavier then normal is the pantry and that is centered over my wide-stance axels. Even clothing would have balanced out because the parents gear is mainly in the front or center coat closet and the kids is in the rear.

[Turtle_n_Peeps]

99% of the time when people talk about "true" sway it is because of lack of tongue weight.

Water is heavy. Some trailers are of poor design. The further the fresh water tank, black or gray tanks are away from the axels the more potential for screwing up the weights and balances of the trailer. Some trailers will change dramatically by taking water out of one tank and putting it in another. (Fresh to black....etc.)

Trailers that are right on the border of sway are very particular in the way they are loaded. I know because I have one. If I load heavy stuff in the back I can turn a well handling trailer into a nightmare trailer. Just a few 100 lbs can make a BIG difference with some trailers.

Check the way the trailer is loaded. Both with water and things.

[Rough31]

Campigloo... Not offended at all... would love to upgrade to the 2500 Diesel. And the torsion bars are definetly a consideration... My first thought when the issues started were that after three days they were feeling the strain... One of my first solutions (unsuccessful) was to flip them around to reverse the load on them.

[Rough31]

I actually checked the bolts several times on the trip and everything was tight.

My trucks payload capacity is 1928lbs. My family is young, so even with my fat butt we only total 600lbs. The listed hitch weight for the trailer is around 850 lbs, leaving me 500lbs to spare on payload capacity and 150lbs on the hitch spring arm capacity. I know the real numbers will be different, but I would be surprised if I exceeded those guidelines.

And I have to go back to.... My set up was working. I am very careful to not significantly change my payload between trips and keep things as balanced as possible. And nothing changed in my payload between the first and third days of the trip. Even through the downhill portions in the mountains of West Virginia I had no concerns. It was not until the straight highways of Georgia on day three that I started to have sway concerns.