Sway

ValerieD

Member
Nov 14, 2021
43
Portland OR
Our pup has12 inch tires which my husband blames for the fact that we can't go over 58 mph without it starting to sway. We've got most of the weight loaded to the front and it travels level. Is that probably the cause or is there something else causing it. It's a Viking 2109 being pulled by a Ford Ranger.
 

jmkay1

2004 Fleetwood/Coleman Utah
Oct 10, 2013
7,622
Northern Virginia
It Might be best to weigh the camper to ensure you have between 10-15% camper weight on the tongue. Too much and too little can cause sway. Also try and lower the ball a bit. How old are your camper tires? As crazy as it sound I’ve had it happen where brand new tires resolved a slight sway problem for me. Now camper tires sometimes do have a speed limit and it would be good to remember but it shouldn’t cause sway If you go over that limit.
 

Sjm9911

Super Active Member
May 31, 2018
11,947
Nj
Also try to ballance the load of packed items, so not all heavy on one side. You can also get a friction sway bar for the pup. They are not too muck money, at most 50$
 

davido

Super Active Member
Jul 17, 2014
1,367
My checklist:

  • Not enough weight up front.
  • Too much weight in back.
  • Balancing left-to-right.
  • Trailer is towing mostly level (ball height, suspension sag).
  • Vehicle is towing mostly level, too (excessive suspension sag in back, suspension lift in front)
  • Tire pressure too high (reduced traction, increased bouncing and skipping).
  • Tire pressure too low (increased flexing of the sidewalls / tire lateral roll).
  • Inadequate suspension (shocks are bad, springs too weak)
  • Tire tread (possibly too little traction).
  • Steering linkage is aging (bump steering).
  • Speed is too high.
  • Wind conditions are gusty.
I do find that using a weight distribution hitch (to level out the tow vehicle) and a sway control bar provides a substantially better towing experience. That's with my old Bronco, which would have been built on an F150 chassis.
 

J Starsky

Super Active Member
Aug 3, 2017
1,245
East Central MN
Got a grain mill around? How about a DOT truck inspection site? Or a CAT Scale? Go weight the combo. Then weigh each axle. Then unhook and weight the TT alone. Calculate % tongue weight, add and subtract till you're at 17% and it'll ride like a dream. I've set up tri-axle trailers with drill rigs like that, but you need a scale if you want to be right (all the time).

It is worth the effort if you're really having an issue.
 

1380ken

Super Active Member
Nov 7, 2013
2,919
Mass
Can too much tongue weight cause sway if you are way below TV tongue weight rating an TV isn’t sagging. I got a lot of sway at speed and tried to load everything up front , didn’t seem to help much . Also new helper springs on TV
 

Sjm9911

Super Active Member
May 31, 2018
11,947
Nj
You will need the sway controll arm. Unfortunately, sometimes the tv gets the waged by the dog even if the dog isnt that big. Unless you get weights, as stated above, you may be unballanced. You really dont want to tow over 60/65 anyway even if the tires can handle it. Sway, as also stated above can be caused by wind, and faster things passing you. I have also noticed diffrences in type of asphalt, concreate, etc that effect controlling the camper. This was noticable on longer trips with the same load and speeds. So, it can and will change. Get the cheap insurance, friction sway controll arm.
 

davido

Super Active Member
Jul 17, 2014
1,367
I commented earlier on things that increase sway potential. Here are the methods I've found for reducing it:

  • Weight distribution hitch - This serves several purposes. First, it keeps an appropriate amount of weight on each axle; enough weight in front that I don't have reduced steering traction, but also a careful setup that avoids reducing traction in the rear. A WD hitch also puts a little more weight on the trailer's axle, which is also good. The next reason for a WD hitch is to provide me the ability to add weight where I need it without causing any of the issues above (decreasing steering traction, or decreasing rear-axle or trailer axle traction), while also avoiding exceeding the safe tongue weight limits. The weight distribution hitch doesn't directly decrease sway. It does improve your ability to load correctly to reduce sway.
  • Sway control bar - If your WD hitch doesn't have its own sway mitigation, or if you're not using a WD hitch, you really should have a sway control bar. I set one up on my trailer, and it's just a much more solid towing experience. If sway is caused by the trailer having *too much energy* (trying to go faster than the tow vehicle), a sway bar bleeds off that excessive energy right at the pivot point in the form of friction, which translates to heat. The point to stopping sway is removing energy from the trailer. A sway bar does exactly that, and removes it at the most critical place. Sway bars are cheap, and take an hour to install the first time (under a minute to connect once the initial installation is complete). Even if you don't experience sway, get a sway control bar -- it's cheap insurance.
  • Increased weight in the tow vehicle. A heavier tow vehicle relative to the trailer will sway less. So instead of loading everything you can into the trailer, put some of your cargo in the cargo area of the tow vehicle to increase the weight over the rear axle, and to decrease the amount of energy the trailer can take on (reducing the trailer's inertial mass). Don't overdo it. The trailer needs to be a good weight too. But don't overlook the value of keeping some weight in the tow vehicle.
  • No extra weight aft of the trailer's axle. None. Well, almost none. Many trailers put the water heater and fridge aft of the axle. You can't do much about that. But don't store anything else back there.
  • Load the right amount of weight toward the tongue. You want your tongue weight to be greater than 10%, but really targeting 15%. Over 17% you may be putting too little weight over the trailer's axle.
  • Enough weight over the trailer's axle. Again, keep that tongue-to-axle ratio as close to 15% on the tongue as you can. Surprisingly, if your water tank is over your axle, it may stabilize things to carry some water. Just keep the tongue at as close to 15% as possible. Once again, the WD hitch buys you room to do this. Many tow vehicles wouldn't have enough hitch capacity to accommodate 15%, but with a WD hitch you can offset that weight and run at 15% tongue weight without causing suspension sag, front suspension lift, and so on.
  • Brakes - If you feel sway, the clock is already ticking. You don't know (yet) if that sway is going to escalate, and by the time you do know, it's already too late to react. As soon as you feel a hint of sway, tap the TRAILER brake controller (not the vehicle's brakes). Remember, eliminating sway means bleeding energy out of the trailer. Your sway control bar converts pivot energy to heat. Your trailer brakes convert additional forward energy into heat, and much more energy than a sway bar can remove. But don't tap the car's brakes. Already, the trailer is travelling faster than the vehicle when it's swaying. Slowing down the two in tandem may cause a jackknife situation. Gently ease the thumb control on the brake controller. You should practice this so it's second nature. Practice when you feel a gust nudge the trailer.
  • Speed - Don't accelerate into a sway. In theory it can remove sway, but not quickly enough. Plus, you'll be increasing the speed at which you'll find yourself careening out of control at on the highway. Accelerating is the wrong approach.
  • Speed - Keep it down. The propensity to sway increases as a square of speed, so if you go 10% faster, your propensity to sway doubles. If you go 10% slower, your propensity to sway halves. Tow at a safe speed, and reduce that speed when you're towing in gusty conditions or in close proximity to cargo trucks (they create a bow wave effect that will suck your trailer into a sway).
 

davido

Super Active Member
Jul 17, 2014
1,367
Yea, air up the rear tires! Good point.

Good point, to a point.

Too much tire pressure reduces traction, and towing will feel squirrely. Too little becomes squishy and towing will feel imprecise, sloppy.

While's we're discussing points, here's a case IN point: The oil change place mistakenly put 50 PSI into my 1995 Bronco's 31x10.5 LT tires. The tires *could* accommodate that pressure. But it's totally wrong for the vehicle. Towing felt really tenuous. Every bump felt like it was going to send me in the wrong direction. Why? That amount of pressure, with my TV, was enough to reduce overall traction, and also to create some jittery feelings at highway speeds.

I aired them down to where I prefer to keep them while towing: 38psi in front, 40 in the rear. That's still higher than I would drive every day with. But it's not too high.

So yes, air them up, but not so much that traction suffers. The goal is to air them up so that they retain a similar contact-patch profile to where they are when not towing.
 

Sjm9911

Super Active Member
May 31, 2018
11,947
Nj

Good point, to a point.

Too much tire pressure reduces traction, and towing will feel squirrely. Too little becomes squishy and towing will feel imprecise, sloppy.

While's we're discussing points, here's a case IN point: The oil change place mistakenly put 50 PSI into my 1995 Bronco's 31x10.5 LT tires. The tires *could* accommodate that pressure. But it's totally wrong for the vehicle. Towing felt really tenuous. Every bump felt like it was going to send me in the wrong direction. Why? That amount of pressure, with my TV, was enough to reduce overall traction, and also to create some jittery feelings at highway speeds.

I aired them down to where I prefer to keep them while towing: 38psi in front, 40 in the rear. That's still higher than I would drive every day with. But it's not too high.

So yes, air them up, but not so much that traction suffers. The goal is to air them up so that they retain a similar contact-patch profile to where they are when not towing.
The next problem is at what pressure does the tire hold what weight. So, its like a catch 22. Unless you weigh it each time or go slightly over whats you want , its hard to have a set point for towing. No trip or packing is the same. But , as you said, you know when it works and when it dosen't. So you have some leaway. Just dont go under the amount needed for the weight added to the TV with hitch weight added in.
 




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