Suddenly Swaying

[JoeTampa]

First time this year taking the TT out on the road, and suddenly I am experiencing (minor) swaying where I’ve never experienced it before. I literally had to remember that the TT was back there when towing it in the past, and on this trip, I was feeling the sway and was being pulled to the side as vehicles passed me. It was very unnerving.

I don’t have weights to cite currently, however:

* All tires were checked and are at proper inflation pressure.

* Nothing substantive has changed on the trailer in terms of loaded gear - total or position. Trailer is a Jayco 33RBTS.

* Nothing substantive has changed on the truck or with the hitch - Silverado 2500 and Blue Ox SwayPro - with ONE exception - I just put all new tires on the truck.

I can’t imagine that tire choice would impact sway, would it?

Anything else I may have overlooked?

Should I load more weight in the front of the TT and see what happens? I’ll have to get it to a scale, but I we are leaving on vacation in 2 weeks and I want to get a handle on this before I drive it all over the state for a week.

Thanks!

[JoeTampa]

myredracer wrote:

You say you had the right tire pressures. Curious what that is? Should be running the TT tires at max sidewall psi. The truck tires can be run up to, or near the max psi rating. I run our rears on our F250 at 80 psi rear and 75 psi on the fronts. I experimented with lower pressures but found 80/75 gave better handling.

If the WDH setup isn't optimized and the TT isn't level to slightly nose down, the new tires can accentuate sway and poor handling.

Pressures on all tires were per vehicle manufacturer's spec (Chevy/Jayco), not tire max PSI spec.

Trailer was level. I actually stopped on the way home and checked it in a level parking spot of a rest stop. I ratcheted up the chains one link and that seemed to mitigate it slightly due to the increased tension on the sway bars, helping them to more strongly attenuate it. My plan for this trip at the moment is to add dead weight to the front of the trailer, drive slower, and ratchet up yet another chain link. Once I get 400 more miles or so on these tires, I'll put the chains back to the usual link and try upping the speed to see if it recurs.

Again, thanks for everyone's responses thus far.

[myredracer]

Wasn't Suddenly Swaying a movie or was that Suddenly Susan?? :B

We replaced the tires on our truck a few years ago and had also handling trouble in the first few hundred miles or so. I even thought there was a tire issue and considered returning them. We replaced them while away on a long trip. Had them installed and then headed out on an interstate when there was strong gusting side winds. Man, was that a scary experience or what!

I'd also suggest it's the new tires and would just cope with them as needed for a while until the tires are broken in. Then report back here. Your truck is more than capable for that length/wt. of TT.

You say you had the right tire pressures. Curious what that is? Should be running the TT tires at max sidewall psi. The truck tires can be run up to, or near the max psi rating. I run our rears on our F250 at 80 psi rear and 75 psi on the fronts. I experimented with lower pressures but found 80/75 gave better handling.

If the WDH setup isn't optimized and the TT isn't level to slightly nose down, the new tires can accentuate sway and poor handling.

[ford_truck_guy]

In MY opinion ( after having tire squirm-tread flex ) if COULD give you trailer sway..

Because the tow vehicle is constantly moving left to right ( from the squirm ) , the driver is constantly correcting it, that makes for a lot of movement in the rear end of the trailer.....

[JoeTampa]

mkirsch wrote:


Most likely it's been a problem for a while, which was masked by the sway control device. It's now gotten to the point where it is overcoming the sway control device, which is not good.

Take an inventory of what's in the trailer, especially what's behind the axles. You may think nothing has changed, but over time you slowly add-add-add, not really thinking about where you put things, and over time, it adds up. You may find several hundred pounds of unnecessary "stuff" in the rear storage compartments causing your sway problem.

That's the thing - we last took the trailer out in September, and drove several hundred miles from Tampa to Mobile, AL and back - and everything was rock solid. When we got home, we parked the trailer - at most removing perishable food and clothes.

We took the trailer from Tampa to Sarasota recently after changing the tires and the issue was immediately apparent. I had never had anything more than barely perceptible push-pull before, and now it's VERY noticable. I'd never felt the trailer swaying before, and now I do. We didn't add or remove anything in terms of gear from the trailer - so I just don't get it. The only thing that has changed is the tires.

[mkirsch]

Ok, then it sounds like you have a sway problem. Usually in these cases people get a little bobble from the road conditions or a push-pull from a passing vehicle, so the trailer "sways" over and back. *A* sway is not "trailer sway."

If it's oscillating and you need to apply trailer brakes, you've got a problem.

Most likely it's been a problem for a while, which was masked by the sway control device. It's now gotten to the point where it is overcoming the sway control device, which is not good.

Take an inventory of what's in the trailer, especially what's behind the axles. You may think nothing has changed, but over time you slowly add-add-add, not really thinking about where you put things, and over time, it adds up. You may find several hundred pounds of unnecessary "stuff" in the rear storage compartments causing your sway problem.

[Lynnmor]

You may have been on the verge of swaying previously and the new tires put you over the edge. Since sway usually is caused by too little coupler weight, I would fill a tank that is forward of the axle and make a test run.

[demiles]

Uncontrollable sway only happens when you are traveling at or above what is known as critical speed. As you approach critical speed it will start taking longer for oscillations to dampen out. So yes sway can happen intermittently at smaller amplitudes and not need intervention.

[JoeTampa]

In my case, this is sway, verified by the wife in a car behind me and able to be felt in the ride of the truck. The back end of the trailer is oscillating back and forth and coming close to or just over the lane line. The SwayPro does seem to be handling it, and manually activating the trailer brakes does as well, but I’m concerned that it has suddenly appeared.

So is the consensus that new, otherwise suitable tires can cause minor sway to occur until they are broken in? If so, I’ll simply try to put as many miles on the tires as I can before we leave for vacation in a week. If not - what else can I do?

[Grit_dog]

mkirsch wrote:
At least you don't have sway. Tire squirm, push-pull, or something else, but it isn't sway.

Sway doesn't come and go. It starts, and continues to escalate until you do something about it, or it does something about you.

True statement! Some that have never experienced a tail wagging the dog do not understand that there is a difference between "normal" trailer movement and uncontrollable trailer sway.

[mkirsch]

At least you don't have sway. Tire squirm, push-pull, or something else, but it isn't sway.

Sway doesn't come and go. It starts, and continues to escalate until you do something about it, or it does something about you.

[Wishin]

I never had sway, but I did feel more movement with passing vehicles. Especially when they were newer. Unloaded break in was done, but more happened when I was towing. To me, the definition of sway is it will oscillate back and not seem to be caused by anything. I never felt that. I did get pushed around more before they were broke in.

[JoeTampa]

OK, so I get that a new set of tires might have squirm while they are breaking in - or that the tires I have might not be suitable at all based on the type of tire. However - for those of you who did notice tire squirm, did that translate into trailer sway? And did that sway go away when the tires broke in?

Thanks for all the replies thus far.

[Wishin]

I changed from mostly worn down Michelin LTX MS2 tires in size 245/75R16 LRE last year, which were incredibly stable, to Cooper Discover AT/3 tires this year in size 265/65R18 LRE. I definitely notice more tread squirm, but they did improve after towing a bit. We took a 2000 mile trip and I was still happy with them, the steering is not as precise as before on the highway but felt pretty stable by the end of the trip. I noticed improvement in just the first day of driving (250 miles?). The Michelin's, once worn down a little, had a solid rib of rubber along both shoulders of the tire. The Cooper tires have full depth tread blocks, even on the shoulders so the increase in squirm was somewhat expected. I've used this tire before on my dad's truck when they were nearly worn out and they were great then. They will improve over time. The good news is they work much better when not on the pavement, I wanted a slightly more aggressive tread and am not disappointed. If I was never going to go off pavement, I'd have stuck with an all season tire with a more stable tread.

[donn0128]

Had a leased SUV years back, so did not want to put expensive tires on it. So bought a set, ran them for about two weeks. They were horrible.
So the tire dealer replaced them with Michelins, problem solved. So YES tores can and do make a hugw differwnce.

[Grit_dog]

I'm with the group...if the only thing changed is truck tires then that's likely the source. Some tires squirm a bit when new, some don't. Some people squirm a little when their trailer wiggles, some don't.
Otherwise, idk.