Excessive sway on 5th wheel

Purchased new Sailum 235/85/R16 tires one month ago for my 35’ Big Country. Soon as I hit the highway on my trip, it started swaying bad at 50 mph. Slow down and it goes away. I can get up to 60-65 and then it will start again. Let off the pedal and it will stop. Didn’t change anything but the tires. Never did this before with other tires. Stayed as plan on trip hoping it would stop but hasn’t. Really does it almost every time accelerating up a incline. Any ideas or past history on this out there. Plan on taking back to tire shop and checking it out when I return.
 

cookie

Administrator
Staff member
The Sailun tires that you bought are actually very good tires although there is the possibility of having a failure.
In the mean time I would check the air pressure, 110 psi, and the torque of the lugs, 125 foot pounds.
Please update this thread when you find the problem.

Peace
Dave
 

danemayer

Well-known member
I seem to remember some past discussion about some tires not being a good match to the width of some rims. Maybe you're mismatched.
 
Thought that might be the problem on air pressure. Ran at 110, then 100 and now at 90. Still same problem. Torque is good. Will up date if and when problem solved.


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wdk450

Well-known member
When you say "swaying" do you mean the trailer fishtailing side-to-side, or the trailer vertically swaying left-right as it goes down the road???

Have you extensively checked out your suspension system? Bad springs or shock absorbers??
 

RickL

Well-known member
Did you match load range of the new tires to the old tires or did you go up or down? First thing to know is that your wheel width within the tires specs, preferably matching the optimum width. Next is knowing your specific wheel weights. That would help you set the tire pressure to the correct PSI to match your load.

Over inflating the tires can cause a smaller foot print (in tire terms “contact patch”) which may be the reason for the sway. Or lack of pressure to carry the load can create a “squirm” causing the sway. Lastly, I’m assuming you installed trailer tires and not light truck tires. Typically light truck tires have a deeper tread depth then tires designed for trailer applications. This can also result in tread squirm until the initial tread depth starts to wear.

A number of years ago when Bridgestone introduced their new drive tires for semi’s, M726, it came with 32/32nds of tread. At first a number of drivers complained about the squirm as a feeling the truck was on ice. Once the tires wore down the first 4-5 32nds the truck settled down and the tires wore like iron. The 726 have been the gold standard for drive tires for years.

Lastly you may want to jack up each wheel position, loosen the lug nuts, then making sure that the wheels are contacting their mounting surface squarely, tighten and torque the lug nuts in a star fashion to the recommended torque specs.
 
After my long trip,I took trailer back to tire shop and had him balance all four tires. That helped a lot but still not perfect. Can run 70 mph with no sway, but still get some here and there. Trailer parked at our spot in south Texas for the remainder of winter. No trips planned till next September. Will post again if I find anything else wrong. Thanks for the feed back


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TravelTiger

Founding Texas-West Chapter Leaders-Retired
Are you towing level? If not that could be contributing to the sway.


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Bones

Well-known member
My thought is the tires may be bringing to light another issue in the suspension or bearings
 

katkens

Founding Illinios Chapter Leader-retired
I wish you would have answered Bill Knights question on sway. I have friend that was complaining of sway and was actually a problem with the truck. He was having problems at the speeds you are stateing and we found a bad universal joint on the truck.
 

Emma

Member
Sway bars act like dampers that work horizontally. Two sway bars are installed on opposite sides of the trailer hitch and whenever the trailer starts to move to the side, the sway bars, with the help of friction and the brakes of the trailer, will help minimize the amount of sway. Is that right? I have read some information like that in here: https://www.listatrailer.com/do-i-need-a-sway-bar-for-my-trailer/
 
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Piperflyer

Well-known member
Tire pressures all with the different air pressure has a lot to do with trailer sway from left-right. If the pressures on one side aren't close to the pressure on the other a sway will result at higher speeds.
 

TravelTiger

Founding Texas-West Chapter Leaders-Retired
One thing I thought of, maybe there’s a suspension issue? Check for flipped shackles or a broken band on a leaf spring?


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SNOKING

Well-known member
This thread started last fall, and OP stated trailer was going to be in Texas for the winter. I do not see where he reported on the issue this spring/summer!
 

JohnD

Moved on to the next thing...
Sway bars act like dampers that work horizontally. Two sway bars are installed on opposite sides of the trailer hitch and whenever the trailer starts to move to the side, the sway bars, with the help of friction and the brakes of the trailer, will help minimize the amount of sway. Is that right?

Sway bars are used on bumper pull travel trailers...5th-wheel trailers do not need them.

The OP with this problem has a 5th-wheel trailer.

But to answer your question...sway bars on a travel trailer do help to minimize sway.
 
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