Trailer towing wag/sway - weight distribution - demo videos - WOW

[swduns]

I've always been a motorhome person
I've seen dangerous trailer sway out on the road
and I've seen video of trailer accidents due to sway
I often wondered about the dynamics that drives the sway
I saw a video of a trailer model demo of sway due to weight distribution
WOW!
I'm sure the trailer people know all about this
but for the non-trailer people this may be interesting to see

Video of trailer sway accidents:

https://www.youtube.com/watch?v=Z7Kfl97b57s

Video of trailer sway models & weight distribution:

https://www.youtube.com/watch?v=i2fkOVHAC8Q

for a non- trailer guy, the effect of the weight distribution is facinating
I see a lot of people towing loads with sway, I wish could see this.
There are many other YouTube videos on trailer stability & sway that shows this same thing

Steve D.

[nicky8668]

It amazes me how many people load weight behind the trailer axle. Especially those 8’ trailer hauling 16’ steel tubes, which has a good 10’ resting behind the axle. If that trailer doesn’t sway, then Issac Newton won’t be happy.

I once saw a construction dump truck tow a small generator trailer, which looks like 1000 lbs max. That trailer sway left to right at least 2-3’ down the road, I think the driver didn’t even notice anything. Take home message is, if you have enough overkill, sway doesn’t matter.

[tuffr2]

What I noticed is dash cams in the 18 wheelers. 18 wheelers cause travel trailers to go thru air durbulance caused by the 18 wheeler. That starts a push/pull that seems like a lot of people don't know how to handle.

I had one rig that would sway and have push/pull from 18 wheelers. Lucky I was able to keep this rig on back roads most of the time. Zero sway at slower speeds of 35 to 50 mph.

I bought a bigger truck which allowed me to tow without any sway at 72+ mph and even zero push/pull.

It helps to have enough weight on the tongue because not enough weight causes sway. That and I think a short wheelbase on the tow vehicle (TV) also will allow sway IMHO.

[move on]

When I look at that trailer in the YouTube clip it seems like the axle is right in the middle, making it easy to back-end load which will cause it to sway at a low speed. Some manufacturers will design the trailer like this so they can sell it to people with small tow vehicles. Beware.

[Dave Pelletier]

Good info and reminder.

Thoughts;

- All TT's can sway.

- a properly loaded TT with adequate tongue weight will have the sway reducing in amplitude at each arc until it's tracking straight again. An improperly loaded trailer without enough tongue weight will have the sway increasing in amplitude until disaster strikes. NOTE; the video shows several crashes where there was a large load on the back bumper or beyond!

- There are a variety of devices designed to help reduce sway; friction devices, electronic sway control, etc. WD hitches often have a form of friction control built in. The only hitch that will eliminate sway is a Hensley or ProPride that "projects" the tongue weight to near the rear axle. None of these things should be used as a bandaid for incorrect loading!

- having enough tow vehicle won't stop sway but it can stop you from crashing because of it!


2 cents,
Dave

[aether_one]

As a decades long TT puller through multiple configurations of tow vehicles and trailers, these are the factors affecting sway from most to least effect IMHO:

Too little tongue weight
Too much speed
Too short a wheelbase on the towing vehicle
Lack of sway control/mitigation

YMMV and feel free to discuss/disagree.

[Dave Pelletier]

Originally Posted by tfryman

As a decades long TT puller through multiple configurations of tow vehicles and trailers, these are the factors affecting sway from most to least effect IMHO:

Too little tongue weight
Too much speed
Too short a wheelbase on the towing vehicle
Lack of sway control/mitigation

YMMV and feel free to discuss/disagree.

I can agree with that though I'd say that the tow vehicle doesn't affect sway as much as it is a determining factor in how the sway affects you; the trailer will sway or not due to loading, speed, wind, etc. ......a good tow vehicle mitigates the effects to some degree. Additionally, I'd say that a short wheelbase is one thing that hinders control once sway starts but there are others; weight of the tow vehicle, stiffness of the suspension and tire sidewall stiffness

Dave

[NevadaNick]

In my mind its all about loading and tongue weight. I towed double bumper pulls for several years at Nv speed limits without sway.

[tuffr2]

Most of those sway conditions should never have gotten that far out of control.
Simply reach to the brake contoller and apply braking to the trailer - right?

[Bobby F]

Helpless feeling when it starts. Just remember:

1. Don't touch your own brakes.
2. Quickly apply the trailer brakes if you have a controller.

[nicky8668]

Many of these small utility trailers have flat 4 connectors. No brake to apply. I guess the only thing to avoid this is to properly load the trailer and keep the speed down, especial with a smaller tow vehicle.

[happy2rv]

Worst swaying I've ever seen was a couple of months ago leaving Savannah, GA. I've never experienced significant sway with our 35' TT, but I was on the Interstate behind someone towing a tear drop with, I believe it was a BMW, SUV. I was going just under 70 when he passed me like I was sitting still. That tear drop was all over the place and the back end of the SUV was following it. I still don't know how they kept from completely losing it. I slowed down and backed off because I just knew it was going in whichever direction physics was going to take it at any moment.



They continued north when I turned east, so I don't know if they made it where they were going. If I were experiencing that kind of sway, I'd be slowing down. Of course, I never tow at 90 MPH, so I wouldn't know if mine would sway at that speed



Slowing down, proper equipment, loading correctly, and situational awareness go a long way. I try not to get in a hurry when I'm towing. I KNOW it will take me longer to get there when I'm towing a house and plan accordingly.

[swduns]

I've seen relatively lightweight SUVs pulling fairly large travel trailers & I've wondered first if the transmission in the SUV can handle it and second if the light SUV is heavy enough to manage that large TT. I would expect at least a Tahoe or some type of truck based SUV to pull a TT. I am curious what is the right answer.

[tuffr2]

To me there are two types of RV's.

Type 1 RV'er:

Working people that go to state parks on weekends. I can get to about 6 state parks without getting on the highway. My top speed is close to 55 mph but most of the time it is 45 mph. A SUV would be perfect for this type of RV'er.

Type 2 RV'er:

It is when you get on the highway and travel faster with 18 wheelers in the mix that is the where sway starts to happen. This person wants to travel hundreds and thousands of miles on the highway.

I used a maxed out vehicle for 4 years because I was 'camping' local. It was when I retired and wanted to travel more I had to buy a bigger tow vehicle because my maxed out vehicle would sway.