Controlling Sway Stresses Trailer Frame?

By the way, a sudden and severe swerve while towing a trailer can/will cause the trailer to sway as demonstrated in videos demonstrating the effects on a trailer with and without a sway control hitch.

Please provide the links to the videos you are referencing. I would like to watch them. Hensley, ProPride and PullRite make wonderful hitches for WD. PullRite is a little heavy at 400 pounds but it is likely the best of the three. And if the trailer is not well suited for towing the hitch can 'bandaid' a serious situation so sway is 'contained' so it cannot get out of control. Sway is still there, still trying to occur, it is just controlled. And worse, there is still something wrong with the trailer.

I don't totally agree with you nor was I referring to trail bow wave, but neither am I here to argue the point. It doesn't help the original poster.

In your original post you addressed nothing regarding the OP's frame stress failure issues. You did expound on why you think (in your opinion) you need a sway feature when towing as to it being insurance . I only addressed your concerns and the things you offered as possible situations that would initiate a "possible" sway episode. They won't with a properly loaded trailer. A couple years ago in the Airstream magazine sway was well defined and exlained using physics, moment arms, and loading issues, not opinions. But, if you feel that a sway feature on your hitch works, then use it. There is a value in peace of mind, reagardless if it addresses a real situation, or is warranted.

jmtandem wrote:

I am of the opposite opinion. I believe anti-sway bars are a necessary insurance. Under perfect conditions, they may not be needed. However, driving conditions can be unpredictable and change in an instant. i.e., extremely strong wind gusts, swerving to miss a obstacle in the road or an animal darting across the road, etc. Driving properly is fine and dandy, but also may require drastic evasive actions when lease expected.

None of the things you mentioned should ever put a trailer in a sway situation. Sway is defined as when the trailer is trying to go faster than the tow vehicle and is characterized as increasing arcs of oscillation. It is not a gust of wind or an 18 wheeler bow wave hitting the trailer for a second and moving it around a little. That is not sway. Your insurance should not be a sway feature on a hitch but the trailer only brakes. That is the only thing that can slow the trailer speed down enough; hitches don't slow the trailer. Think through sway, it cannot occur going uphill, the trailer is drag or trying to go slower than the tow vehicle. It cannot sway. Use the trailer brakes, that is what they are there for if you think you will be having a sway episode. The guys that deliver trailers to dealers from the factory don't use sway features and know that if the trailer has at least ten percent of the total trailer's weight on the tongue, it won't sway.

I don't totally agree with you nor was I referring to trail bow wave, but neither am I here to argue the point. It doesn't help the original poster.

By the way, a sudden and severe swerve while towing a trailer can/will cause the trailer to sway as demonstrated in videos demonstrating the effects on a trailer with and without a sway control hitch.

I am of the opposite opinion. I believe anti-sway bars are a necessary insurance. Under perfect conditions, they may not be needed. However, driving conditions can be unpredictable and change in an instant. i.e., extremely strong wind gusts, swerving to miss a obstacle in the road or an animal darting across the road, etc. Driving properly is fine and dandy, but also may require drastic evasive actions when lease expected.

None of the things you mentioned should ever put a trailer in a sway situation. Sway is defined as when the trailer is trying to go faster than the tow vehicle and is characterized as increasing arcs of oscillation. It is not a gust of wind or an 18 wheeler bow wave hitting the trailer for a second and moving it around a little. That is not sway. Your insurance should not be a sway feature on a hitch but the trailer only brakes. That is the only thing that can slow the trailer speed down enough; hitches don't slow the trailer. Think through sway, it cannot occur going uphill, the trailer is drag or trying to go slower than the tow vehicle. It cannot sway. Use the trailer brakes, that is what they are there for if you think you will be having a sway episode. The guys that deliver trailers to dealers from the factory don't use sway features and know that if the trailer has at least ten percent of the total trailer's weight on the tongue, it won't sway.

I find it necessary to disagree with that statement. I had just such a trailer!
It was home-made, and improperly built. I tried a couple of times to load that thing so that it would not sway. Nothing I could do worked. It would begin to oscillate side to side in ever increasing arcs. Luckily, I managed to slow down and get the rotten thing under control every time (it did not have brakes). I had to use it for two trips, and then I sold it. I advised the buyer that it absolutely had to be rebuilt before taking it over 40 MPH! I hope he did!
IMO, a properly built, properly loaded trailer, with the proper tires inflated to the proper pressure, should not sway. If it does, find out why, and FIX IT!
Then, and only then, if it gives you a warm fuzzy feeling to have it, get the sway control gadget.
As for stress on the trailer frame, of course it does. Anytime metal flexes, it causes stress. It is just the nature of the stuff!

Think of it like a riding bull being held in a squeeze chute at a rodeo. The bull can't move much but he can thrash a little and throw himself against the confines of the chute. If the bull is allowed to do that long enough, he will hurt himself.

Another analogy would be to put a hammer's head in a vise. Yank and push on the hammer's handle with all your might. At first it won't move but after enough push-pull cycles the handle will fail.

Even the best sway control can't 100% stop the movement. It may be slight but it's still there, being restrained by the mechanism. I'm just wondering what kinds of stresses that puts on the trailer tongue and frame, and how long a trailer would tolerate those forces before something broke.

It would be interesting to get an absolutely awful trailer, hitch up with a Hensley or Propride, and hit the road to see if anything would break.

I don't understand how you could be stressing the frame when there is virtually no movement - I'd think the actual sway occurrences would be more damaging.

I used a Propride 3P for two seasons before the new 5er and i'll say that towing a 5er or a TT with a Propride feels about the same.

4X4Dodger wrote:
.................
I am of the opinion that Anti Sway bars are unnecessary. Virtually any trailer properly loaded and properly driven will not "sway"........

I am of the opposite opinion. I believe anti-sway bars are a necessary insurance. Under perfect conditions, they may not be needed. However, driving conditions can be unpredictable and change in an instant. i.e., extremely strong wind gusts, swerving to miss a obstacle in the road or an animal darting across the road, etc. Driving properly is fine and dandy, but also may require drastic evasive actions when lease expected.

This is an unusual question but I think the answer is simple:

No trailer has an intrinsic proclivity to sway. If it does indeed sway there is something wrong that can be corrected, axles out of alignment, bent axles or wheels, really terrible load balancing, or just not knowing how to drive it properly.


I am of the opinion that Anti Sway bars are unnecessary. Virtually any trailer properly loaded and properly driven will not "sway".

I do think your assumption that the sway bars are just a bandaid that will not really solve the problem is correct. You must address the underlying issue.

Let's say I have a travel trailer with a BAD sway problem. Rather than fix the problem, I decide to "fix" the problem with a Propride or Hensley.

Even though the trailer is now "fine," underneath all that it is still TRYING to sway. The Hensley/Propride is stopping the trailer from getting out of control, but the trailer is still slamming side-to-side against the sway control.

How long before something breaks?

Sway control features are often 'band-aids' more than 'insurance' in case something goes wrong. They should not mask a known problem; the problem should be fixed and in some cases it is a problem with how the trailer is loaded and not enough tongue weight, poor design, or perhaps incompatability with the tow vehicle. In any event waiting for a part to break is not smart regardless how long or not that takes.