Anti Sway Systems - Necessary or Marketing Con?

[4X4Dodger]

This may open a Pandora's box and bring down a lot of criticism on my head but the question really remains a valid one I believe.

Are Anti Sway bars (Like the Hensley) really necessary or a crutch for those that either cant drive a trailer effectively or have an out of balance rig? Are they a multi million dollar business out to convince you you really need one when you dont OR are they really filling a needed gap in TT towing safety?

First a little background: Despite my newness to this site, I have been towing trailers on and off most of my life (a good 45 years of driving) and towed everything from a small U-Haul to a 53 footer with a GVW of 80,000lbs. I have held a Class A CDL with endorsements for Doubles, Triples and Tankers for over 20 years and owned my own trucking company (10 trucks/25 trailers doing logistics) I have for a good share of my life lived overseas where I have seen every possible combination of tow vehicles and trailers most of which most Americans would be horrified to think actually are driven on the road.

No matter what I have towed or with what vehicle I have never felt the need for an Anti-Sway system. Right now I tow my 30 foot Gulfstream Innsbruck with my Dodge 2500 4x4 HD 5.7L Hemi.

I'd like to hear the arguments for and against. Are these systems just taking the place of proper training and practice or are they a true necessity? AND do they instill a "False sense of Confidence" when driving an unbalanced or badly loaded Rig?

NOTE: I am not trying to be willfully provocative here but am truly interested in your thoughts.

[4X4Dodger]

mosseater wrote:
I read through the entire post. There's a lot of doubters, a lot of specualtion. What I didn't see until the previous post was anybody who had seen or dealt with real sway. Not being blown around or pulled by road joints, or even emergency manuevers. Real sway. I have seen it. And it's ugly.

It won't matter how good your skills are or how big your rig is if it happens. It's the perfect storm, and you're lucky if you end up with the rubber side down. You won't have time to do much thinking. The rig I saw was an F-150 longbed hauling a small (4000 lb?) excavator at about 30 mph. It started gradually and quickly crescendoed to an all-out "S" festival, which had the wheels of the truck and trailer both off the ground almost a foot. It started by itself and ended when it was done. It was clear the driver was along for the ride. Period.

I know most of you will blow this off. That's fine, the choice is yours. All I can say is the anti-sway systems on the road will hopefully allow a margin of control to exist which might allow you to regain the composure of your rig if it ever happens. Whatever else a WD/anti-sway system might or might no do safety-wise, I can't really say. I haven't seen credible testing that absulutely puts the issue to rest. I can say that what most people think is "sway"....isn't. If you ever get a chance to see it or experience it, you will be astounded. It almost seems supernatural to observe.

First of all with all due respect NOTHING happens in a vacumn. That sway was INDUCED by some force acting on the trailer or TV or both. Most likely, in the absence of any other obvious sources, it was driver induced.

The trailer and load you describe are problematic and often loaded incorrectly. Or possibly OVERLOADED.

Once the sway begins if the driver slows, the sway motion will increase. If it gets to the point you describe it is VERY difficult to recover. The forces involved tend to reach a point of Harmonic Oscillation which will continue to increase until it is interrupted by other forces.

But no matter what. There was a PHYSICAL reason for this,it did not happen "all by itself" and My bet is that if investigated carefully it would be found that it was a result of improper loading and driver input.

It is scary to see but I am not sure that is a reason to be sold on a sway bar system. NOTHING can replace learning to LOAD it and DRIVE it properly.

[4X4Dodger]

E&J push'n wind wrote:

4X4Dodger wrote:
Let me clarify that when I wrote about the distance between the pivot point and the AXLES I mean the TRAILER axles NOT the tow vehicle axles. It is this distance that truly affects how a trailer tows. I question whether the distance from pivot to TV axle has any great affect at all. This is a weight issue.

One reason that the axle distance matters is overhang on the rear. The greater the overhang beyond the rear axles the more the Airflow works against the sides of the trailer...with a longer lever arm than if the axles were farther to the rear. This would cause sway.

Lets use your example. Lets place the wheels on the trailer all the way at the rear like on a tractor trailer combo. Looking at the pivot point on a 5th wheel trailer and a conventional hitch or a pintle hitch. Now lets place lateral force against the pivot point on the 5th wheel hitch and lateral force at the pivot point on the conventional hitch. That wind force that you speek of works forward of the trailer axles as well. Difference is with a 5th wheel hitch, that leverage I spoke of earlier doesn't have as great an effect on the pivot point on the 5th wheel hitch as it does on the conventional merely because there is virtually no leverage at the pivot point because the pivot point on a 5th wheel hitch is directly over the center line of the rear axle. With a conventional hitch that force exerted by the wind forward of the axle (on TT) has a compound effect because of the leverage created by the distance of the pivot point behind the rear axle (on TV).

Now, if you will. Move the trailer axles to about 2/3 the distance form the pivot point like on many TT's. That wind again that you spoke of has a multiple effect in that it works against you in one direction as a passing vehicle begins to pass and pushes against the back of the trailer aft of the center line of the axles. As the passing vehicle reaches the trailer axle center line it begins to work in the opposite direction as it continues to push against the side of the trailer, once past the axles, that push is opposite it was before it "crossed" the center line of the trailer axles. This is where "sway" begins to occur. Again only because of the leverage created by the distance of the pivot point behind the center line of the rear axle of the TV.

That lateral force is eliminated with a 5th wheel hitch setup. The placement of the hitch directly over the center line of the TV rear axle makes it so that there is absolutely no leverage on the TV. Not so with a conventional hitch, again.., that lateral force against the hitch is working against the TV in as much as it has leverage to move the TV by the later force working against the hitch. The longer the distance behind the center line of the rear axle of the TV the greater the leverage. Can you see it? I hope I was able to explain what I am trying to get across.

Now with the traditional friction sway control, if the friction is overcome problems can begin. With the "premium" hitches (and this is where the firestorm begins) the pivot point is "changed." I'm not an engineer so I can't and wont attempt to explain the math. The only one I can explain is the Pull Right where the pivot point is literally and physically moved forward to the center line of the rear axle (or as near as possible).

Either way, tested by an independent organization or not. You can't ignore the physics of it. With the friction type of control, if you make it "harder" for the trailer to pivot. It accomplishes what it designed to do, create tension so as not to allow it to pivot so easily. With the "engineered" type, the possibility of sway is engineered out.

The question you ask about it masking a bad setup. I'm sure beyond a doubt that there are setups out there like that where someone maybe happy as a lark (with there sway control) all the while they are a ticking time bomb. I am equally sure that there are folks out there that need a sway control of some type (and are without) that are an accident waiting to happen. And there are those that have it that perhaps don't need it and so on and so forth. You get the idea!

I was speaking of AIRFLOW along the side of the trailer and didnt make that clear I am afraid.

You are right however that a force = wind from the SIDE, MAY have the effect you say IF it was localized, which it isnt. It tends to be fairly evenly spread over the entire side. This should not cause the sway you might think. However it would tend to RESULT in sway as the driver tries to compensate for the force of the wind.

To claim as you do that in a fifth wheel set up there is "NO LEVERAGE" by the trailer on the tow vehicle is a misunderstanding of the physics. There is significant leverage. Leverage = force; There are forward, rearward and side (lateral) forces as well as Yaw forces put on that fifth wheel. There is also friction between the surfaces (even greased) that play into this. A simple example of the forces upon your fifth wheel: drop one side of your trailer axle into a low ditch; the forces on your fifth wheel may be enough to loft your opposite rear TV axle OFF the ground. This is an extreme example but it clearly illustrates the forces at work. The other extreme example of forces on the fifth wheel is jackknifing. Being over the TV axles may help stability but it DOES NOT eliminate the forces involved.

The REAL issue is WHY is the trailer swaying in the first place. Is it driver induced sway? Improper design of axle placement vs trailer weight? or a TV that is less that 1/3rd the overall weight of the fully loaded trailer? If sway is induced by weather conditions or being passed it is often made worse by driver response (reflexively slowing or braking when in fact a slight acceleration is the right move and will usually result in the sway disappearing fast)

If the sway is DESIGN induced this can probably be fixed with different loading in some cases. (of the trailer) or a different TV.

BTW: most tractor trailers do not keep their axles all the way rearward this overloads the Drive axles and may not be legal in some states due to "bridge" laws. Where having the axles all the way to the rear really helps you is in parking in reverse in very tight spots. This allows the trailer to pivot at the far rear end and it can be spotted very precisely. I know to some this may sound counter intuitive but it's true.

[mosseater]

I read through the entire post. There's a lot of doubters, a lot of specualtion. What I didn't see until the previous post was anybody who had seen or dealt with real sway. Not being blown around or pulled by road joints, or even emergency manuevers. Real sway. I have seen it. And it's ugly.

It won't matter how good your skills are or how big your rig is if it happens. It's the perfect storm, and you're lucky if you end up with the rubber side down. You won't have time to do much thinking. The rig I saw was an F-150 longbed hauling a small (4000 lb?) excavator at about 30 mph. It started gradually and quickly crescendoed to an all-out "S" festival, which had the wheels of the truck and trailer both off the ground almost a foot. It started by itself and ended when it was done. It was clear the driver was along for the ride. Period.

I know most of you will blow this off. That's fine, the choice is yours. All I can say is the anti-sway systems on the road will hopefully allow a margin of control to exist which might allow you to regain the composure of your rig if it ever happens. Whatever else a WD/anti-sway system might or might no do safety-wise, I can't really say. I haven't seen credible testing that absulutely puts the issue to rest. I can say that what most people think is "sway"....isn't. If you ever get a chance to see it or experience it, you will be astounded. It almost seems supernatural to observe.

[TenOC]

In 1956 my brother (with me as shotgun) pull a 26' TT with a Ford 4 door sedan from TN to CA. No TT brakes no sway control. If he got above 45 MPH it would fish-tail like mad -- no interstate most 2 lane highways. I think I need to change my pants a few time during that trip. . . .:o . . . Yes, anything can be done, but RVing is ENJOYING the trip.

[TInmania]

4X4Dodger wrote:
My grandmother drove her '32 ford coupe pulling a quite big trailer...all the way down Route 66 to San Bernardino, Calif.

I bet they didn't make it through Oatman, Arizona without help. That was one of the most dangerous sections of Rt 66 back then. It was not bypassed until 1953 (via Kingman, AZ to Needles CA--now part of I-40).

There was a gas station right before Oatman, Cool Springs, that used to help many folks through that part of Rt 66, including many Grapes-of-Wrathers.



Mike

[E_J_push_n_wind]

BurbMan wrote:
Good explanation E&J. I'm not an engineer either but there are 50+ pages of diagrams and engineering explanation in this sticky thread about how the HA and PP work

Ya know, I'm aware of that sticky. I've looked at it myself. I don't know why I didn't refer to it but thanks. Good save!

[dadmomh]

We always use the Blue Ox 1000 with sway - previously an Equalizer. Our trailers and tow vehicle need that stability. As noted, you have a lot of experience towing big, small and in between, but driving an 18 wheeler is a lot different than a travel trailer behind your truck. Winds, gusts from the large rigs, unexpected crisis situations....the WDH and sway could save your hide. Nothing is a 100% guarantee, but in the interest of safety for you, your family and the rest of the road, it's pretty cheap insurance. The smaller the trailer does not necessarily mean there is less need for WDH/sway....they're lighter and more susceptible to winds. For a few minutes to hook up, around $500 in cost for a quality one and the peace of mind, suggest you add that.

[BurbMan]

E&J push'n wind wrote:
With the "premium" hitches (and this is where the firestorm begins) the pivot point is "changed." I'm not an engineer so I can't and wont attempt to explain the math. The only one I can explain is the Pull Right where the pivot point is literally and physically moved forward to the center line of the rear axle (or as near as possible).

Good explanation E&J. I'm not an engineer either but there are 50+ pages of diagrams and engineering explanation in this sticky thread about how the HA and PP work. Technically the 4-bar linkage uses geometry to create a "virtual pivot point" ahead of the rear axle of the truck, so that the performance of the trailer mimics that of a 5er where the kingpin hitches in the bed just ahead of the rear axle. Simply, I show folks that movement of the cams only allows the TT to move side-to-side if it also moves forward. Think of a "U", with the trailer coupler at the bottom of the "U" and the open ends attached to the truck. The "U" is the only path that the trailer coupler can follow. Moving to the side it must come closer to the truck and when the hitch is in tension when towing down the road, it's not possible for the TT to go faster than the truck. The caveat is that you're brake controller must be set up properly to deal with situations where the TT could be moving faster than the truck, such as when the truck begins braking, etc.

I don't agree that the only beneficiaries of premium hitches are those who are overloaded...I am well under every rating and still enjoy the stability of towing with a Hensley.

[x96mnn]

Some people need them and some people do not. I think they are a great solution for those who have jumped into a deal without the ability to tow handle it. As well I think some drivers such as myself who have had bad experiences will spend extra money on a hitch for peace of mind.

Does it mask it or fix it I think can be argued based on the setup you choose and stance. I beleive some are engineered to correct a problem after it has started to happen and correct the issue and others stop it from happening. It would be like taking a dual meal and didn't spice to it to make it taste better, is it correcting the problem or just making it taste better. My opinion is if it made it so I could eat it, the problem was corrected.

[goducks10]

E&J push'n wind pretty much summed up our last TT. Heartland for some reason decided to have the TT axles more towards the center of the TT. Even with their WideTraxx spacing the TT still swayed back and forth. Like E&J said the pivot point was the culprit. Even with the used HA that we used I could still see the TT moving back and forth in the mirrors. Only difference between the EQ and HA was the truck was no longer affected with the HA.
If I ever go back to another TT the 1st thing I will look at after choosing the floor plan is to look at the axle placement. IMO it's what separates those that have issues with those that don't.

[coffeebean43140]

I just want to add about my recent experience with the trailer we purchased in Augest of last year.
It is a 2014 Rockwood 8315BSS. We have had many TT and 1 FW since the 90's, but this one can dance!! I feel it is a combination of factors, tires, torsion axles, height, among the major factors.
The TV I had was not the problem, A friend loaned me his duel wheel ton truck and reset the WDH, checked axel and tounge weights and it was still a handful!!
I scratched my head for a couple of weeks, did a lot of reading and asking question and got a ton of information. I pondered all of the information for a couple of more weeks and decided to buy an engineered WDH. This was a difficult and expensive decision to make. I have many years and miles of towing experiencd and I always thought these hitches were overkill. Well I was wrong about that.
IMHO the hitch eliminated the sway issues 100%.
So my experience is and was what performed well for me in the past didn't work for me this time. I still have my Reese Duel Cam, and I will probably use it on something else, but for the current TT the ProPride 3P 1400 was the best choice for me.
Every combination can be different, one has to choose what is best for them and the safety of others in a perfect world.........oh wait.......what did I just say?

[E_J_push_n_wind]

4X4Dodger wrote:
Let me clarify that when I wrote about the distance between the pivot point and the AXLES I mean the TRAILER axles NOT the tow vehicle axles. It is this distance that truly affects how a trailer tows. I question whether the distance from pivot to TV axle has any great affect at all. This is a weight issue.

One reason that the axle distance matters is overhang on the rear. The greater the overhang beyond the rear axles the more the Airflow works against the sides of the trailer...with a longer lever arm than if the axles were farther to the rear. This would cause sway.

Lets use your example. Lets place the wheels on the trailer all the way at the rear like on a tractor trailer combo. Looking at the pivot point on a 5th wheel trailer and a conventional hitch or a pintle hitch. Now lets place lateral force against the pivot point on the 5th wheel hitch and lateral force at the pivot point on the conventional hitch. That wind force that you speek of works forward of the trailer axles as well. Difference is with a 5th wheel hitch, that leverage I spoke of earlier doesn't have as great an effect on the pivot point on the 5th wheel hitch as it does on the conventional merely because there is virtually no leverage at the pivot point because the pivot point on a 5th wheel hitch is directly over the center line of the rear axle. With a conventional hitch that force exerted by the wind forward of the axle (on TT) has a compound effect because of the leverage created by the distance of the pivot point behind the rear axle (on TV).

Now, if you will. Move the trailer axles to about 2/3 the distance form the pivot point like on many TT's. That wind again that you spoke of has a multiple effect in that it works against you in one direction as a passing vehicle begins to pass and pushes against the back of the trailer aft of the center line of the axles. As the passing vehicle reaches the trailer axle center line it begins to work in the opposite direction as it continues to push against the side of the trailer, once past the axles, that push is opposite it was before it "crossed" the center line of the trailer axles. This is where "sway" begins to occur. Again only because of the leverage created by the distance of the pivot point behind the center line of the rear axle of the TV.

That lateral force is eliminated with a 5th wheel hitch setup. The placement of the hitch directly over the center line of the TV rear axle makes it so that there is absolutely no leverage on the TV. Not so with a conventional hitch, again.., that lateral force against the hitch is working against the TV in as much as it has leverage to move the TV by the later force working against the hitch. The longer the distance behind the center line of the rear axle of the TV the greater the leverage. Can you see it? I hope I was able to explain what I am trying to get across.

Now with the traditional friction sway control, if the friction is overcome problems can begin. With the "premium" hitches (and this is where the firestorm begins) the pivot point is "changed." I'm not an engineer so I can't and wont attempt to explain the math. The only one I can explain is the Pull Right where the pivot point is literally and physically moved forward to the center line of the rear axle (or as near as possible).

Either way, tested by an independent organization or not. You can't ignore the physics of it. With the friction type of control, if you make it "harder" for the trailer to pivot. It accomplishes what it designed to do, create tension so as not to allow it to pivot so easily. With the "engineered" type, the possibility of sway is engineered out.

The question you ask about it masking a bad setup. I'm sure beyond a doubt that there are setups out there like that where someone maybe happy as a lark (with there sway control) all the while they are a ticking time bomb. I am equally sure that there are folks out there that need a sway control of some type (and are without) that are an accident waiting to happen. And there are those that have it that perhaps don't need it and so on and so forth. You get the idea!

[TomG2]

4X4Dodger wrote:
.....snip......My main question really is this: Are these products really improving something or are they masking a dangerous combination of over-weight, out of balance rigs and driving skills?

And why is it that some people driving nearly identical rigs dont experience the same problems and feel very differently about these products?

I dont claim to have the answers...but I think the questions deserve airing and discussing.

It is called the "Placebo effect". The way it works is, "If I paid for it, I must need it and it must be good". Properly setup tows do not sway, with or without fancy hitches. There are too many factors to a great setup to list them all here. It will be a welcome day when empirical data is available on this subject, not just guesses.

[4X4Dodger]

proxim2020 wrote:

Speedogomer wrote:
I'll put it this way...

For many years people drove without seatbelts, most of them are alive today, never had an issue.

For a long time cars didn't have ABS or airbags, most people who drove those cars are fine today.

Cars didn't have crumple zones, tow ratings were a recommendation, and WDH with sway control was unheard of.

People all the time like to use the argument "we never had those safety things in my day and I'm fine". That's because every person who isn't fine, is dead from the lack of safety equipment.

Its an additional safety measure, something you may not ever need, just like a seat belt. You may ride around for your whole life unbelted and be fine.

I'm a paramedic, and trust me when I say this, seeing just one dead kid face down in a ditch after being ejected from a vehicle because he was not restrained with a seatbelt... Makes you a believer in seatbelts. For every story that you have about " I know a guy who was thrown out of a car and would have died if he wasn't", I have 100 stories of people who would have been alive with just a headache if they were belted.

Point being, even with a large truck, its a modern safety tool and can help avoid trouble.

I agree with you 100%. It's like the fire extinguishers I have in my home. I take plenty of precautions so that I never have to use them. I look at them everyday and hope that they'll never have to come out of their mounts for an emergency. If a situation comes up where I need it, boy I sure will be glad that I had it.

Back in school, we were having a conversation about the difference in the life expectancy between men and women on average. The professor ran down a list of why men have a higher mortality rate than women. His number one reason, which is backed by studies, was that men are naturally more prone than women to take "unnecessary" risks. As we age the level of unnecessary risk drops, but it's somewhat omnipresent and never really equates to the level of our female counterparts. That's something that will stick with me forever and made me question a lot of decisions since.

Sway control is just insurance really. As with all forms of insurance you can buy a lot or a little. You may spend your who life and never need it. But having some insurance and never needing it is better than needing it and not having it. For me, even an inexpensive sway control system is still a wise investment. A 10,000 lbs+ combo getting out of control can do a lot of damage. It's just not worth the risk to me. Even experts have days when they run across something that they've never seen or experienced before and need help.

The safety argument you make is an interesting one. But one that I don't think can be proved.

Where is the testing done by an independent agency on a skid pad under controlled conditions to actually prove that these products work as many think they do? What I fear is that these have been so successfully marketed as a Safety Enhancement with no real testing to back that claim and so many believe it without question that it has taken on a life of it's own. I for one am not convinced one way or the other. I don't claim to know whether they work or not. But I would like to see some testing from someone other than the MFG's.

Secondly your safety equipment argument made above is really a straw man argument. No one is saying that good proven safety equipment shouldnt be used or adopted. But it should be proven effective first.

My main question really is this: Are these products really improving something or are they masking a dangerous combination of over-weight, out of balance rigs and driving skills?

And why is it that some people driving nearly identical rigs dont experience the same problems and feel very differently about these products?

I dont claim to have the answers...but I think the questions deserve airing and discussing.

[camperforlife]

Most of the time you don't need one but there are times that it will save your butt. I was nearly blown off the road in a mountain pass high wind area and I was only towing a pop up. If someone was next to me it would have been a disaster. Years later I went through the same area with 28 footer and sway control. Wind was not as high and I was not going as fast but it still was not a pleasant experience.

I know that 99% of the time I won't need it, I use it for that 1%. Same reason why I have fire insurance on my home.