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]

E&J push'n wind wrote:
First off let me say I am not an engineer and I could't explain the math to you even with a slide rule. That said.., not including doubles and tripples, the idea of a 5th wheel hitch having a sway issue.., well I just can't see it.., as you have said. The pivot point of a 5th wheel hitch, that makes ALL of the difference. At that point there really is no possibility of sway. The pivot point is usually directly over the axle. Contrast that with the pivot point on a conventional hitch being behind the axle. At that point the towed vehicle has leverage on the towing vehicle and that is amplified by the length of the overhang behind the the axle. You never have that issue with a 5th wheel hitch.

The sway you see with doubles and tripples occurs because these vehicles are coupled similarly to a conventional hitch (pintle hitch). Pivot point on tow dolly behind axle on preceding vehicle. Multiply this by two hitch points (with tripples) and the problem is compounded.

A 5th wheel trailer by its design cannot sway as we understand swaying again because the pivot point is usually directly over the center line of the rear axle of the TV. With semi's the added advantage is that they have adjustable hitches where the hitch can be moved forward. I know that is usually associated with loading but the idea of the hitch forward of the center line of the rear axle I think helps to see how sway would be, I dare to say, impossible provided all things being equal. I'm not speaking about the unseen circumstance but even with that I can't see it.

As for sway control, it is going to depend on each individual setup. You can't throw a blanket over it and say it covers it all either way. Some will need it and some will not. That said, as the seat belt and ABS ideas were floated. It does not hurt to have it and it is better to have it and not need it vs. needing it and not having it. I would hate to be in the latter.

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.

[hotqld]

I am surprised there is no discussion on the Electronic Sway Control, where sway is measured on the TT then the left or right brake is applied at a variable power level to steer the TT back to centre behind the TV.

[E_J_push_n_wind]

First off let me say I am not an engineer and I could't explain the math to you even with a slide rule. That said.., not including doubles and tripples, the idea of a 5th wheel hitch having a sway issue.., well I just can't see it.., as you have said. The pivot point of a 5th wheel hitch, that makes ALL of the difference. At that point there really is no possibility of sway. The pivot point is usually directly over the axle. Contrast that with the pivot point on a conventional hitch being behind the axle. At that point the towed vehicle has leverage on the towing vehicle and that is amplified by the length of the overhang behind the the axle. You never have that issue with a 5th wheel hitch.

The sway you see with doubles and tripples occurs because these vehicles are coupled similarly to a conventional hitch (pintle hitch). Pivot point on tow dolly behind axle on preceding vehicle. Multiply this by two hitch points (with tripples) and the problem is compounded.

A 5th wheel trailer by its design cannot sway as we understand swaying again because the pivot point is usually directly over the center line of the rear axle of the TV. With semi's the added advantage is that they have adjustable hitches where the hitch can be moved forward. I know that is usually associated with loading but the idea of the hitch forward of the center line of the rear axle I think helps to see how sway would be, I dare to say, impossible provided all things being equal. I'm not speaking about the unseen circumstance but even with that I can't see it.

As for sway control, it is going to depend on each individual setup. You can't throw a blanket over it and say it covers it all either way. Some will need it and some will not. That said, as the seat belt and ABS ideas were floated. It does not hurt to have it and it is better to have it and not need it vs. needing it and not having it. I would hate to be in the latter.

[TomG2]

Don't get me wrong, I understand that some people want and need some kind of sway control. I just don't happen to think that little bit of friction is going to change what happens in an all out emergency maneuver. Is the friction enough to keep the trailer straight behind the tow vehicle during normal maneuvers like going around a corner or backing into a campsite? If not, how is it ever going to keep thing straight when the brakes are locked up and the wheel is turned from lock to lock? The answer is, it won't. In the mildest of sway conditions, it may help a little.

[fallsrider]

My NTU trailer came with a WDH and single friction bar. I use both all the time. I like the fire extinguisher analogy. Hope to never need it, but I believe it will give me more of a fighting chance should I ever find myself in a panic situation. I know it is not a Hensley or ProPride, but it is sure better than nothing.

[TomG2]

If you folks get peace of mind from that little friction bar or dimples on a hitch bar, then more power to you. I too have slammed my trailer from side to side to see if there was any hint of loss of control. There wasn't. If some fool decides to knock me off the road, only good luck and driving skills are going to keep me out of the ditch, not some dimple.

[Community Alumni]

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.

[BurbMan]

Good article gomer, thanks for the link. Here's a clicky.

[Slowmover]

Why make this complicated? Buy a Hensley and use the 30-day guarantee. No more questions afterwards.

I took mine out of the installing dealer and did throttle-on maneuvers at Interstate speed for over a mile that would put any conventionally hitched or 5th wheel hitched trailer and tow vehicle on its side. I could no more shake that 34' TT off than I could my shadow.

That left me with 29.5 days of money back guarantee I never used.

.

[allen8106]

Doug33 wrote:
My 2 cents: I find sway control an absolute necessary and do not use it as a crutch. Even with the sway control I am very careful when I tow. I find it particularly important when I'm passing or being passed by large trucks.

I've seen many RVs on the side of the road (in person and on news stories) flipped over and destroyed. An accident caused by out of control sway RV is usually devestating and sometimes lethal.

I see similarities between sway control in towing and anti-lock brakes in a car. How many lives and accidents have anti-lock brakes saved since they were placed on cars? I know anti-lock brakes have saved me a few times from losing control and getting into accidents.

Keep in mind that just as there are automobile drivers of all experience levels, there are also RVers of all experience level. So just as anti-lock brakes can prevent accidents, anti-sway can prevent accidents. You can call it a crutch, but I look at it as an insurance policy. And I have a lot less white-knuckle driving experiences because of it.

And don't tell me the big rigs don't sway. I've seen them on the highways during windy/gusty conditions and they have a difficult time keeping everything between the lane lines!

And it isn't like anti-sway control is that outrageously expensive. So to me it is a no-brainer.

Agree 100%

[SprinklerMan]

I look at it this way ....Braking , the WD hitch helps even out the Tow Vehicle , keeping the nose down . The front brakes work better , than without a WD hitch . In my opinion .

[Speedogomer]

4X4Dodger wrote:
To Stevec22:

I dont beleive the 5th wheel really has anything to do with it as trailers do sway that are attached to 5th wheels (doubles and Triples) because of the short distance between the pivot point and the axles and because as I said in my post the turning factor of the dolly.

And I have seen many a 5th wheeler TT going like mad swaying down the road.

And that really wasnt why I mentioned tractor trailers. I was using the tractor trailer comparison in regards to the weight ratio between the tow vehicle and the Trailer...because many seemed to indicate sway was a function of the tow vehicle weight vs trailer weight..

Your comment about speed is interesting. Generally while traveling forward with some pull, the trailer should not sway whether you are going 35 or 65. Its when you drive erratically, change lanes abruptly, brake without trailer brakes adjusted properly that you get the sway.

However if you really want to haul your TT at 70+mph then aerodynamics may come into it and you may experience some lift under the trailer which may induce some sway...where exactly that speed point is is different for every trailer I am sure. I do agree that speed certainly can be a factor.

I can't explain the math, but trailer instability is directly related to speed. This is a good article that tries to explain it...

http://oppositelock.jalopnik.com/tow-me-down-1609112611

[hotqld]

We are in Australia and reckon best to apply current anti sway technology.
We have a Funfinder USA made 24 foot fully loaded 6000lbs
Tug (TV)is a Jeep Grand Cherokee WK 3 lTR diesel a little overloaded at times @ 6750lbs.
To improve stability we have fitted load bearing shocks and HD springs to the Jeep and added shock absorbers to the TT.
Increased the TT tire loading specs from 1400lbs to 2800lbs.
Taken air cond off roof...weight up high seems dumb, taken the spare wheel off the back and mounted under the TT above the axles.
We load trying to keep weight out of the ends, and over and forward of the TT axles and maintain 675lbs hitch weight.
The rig is stable to tow at 60MPH with no WDH / FSC but we never exceed 50 - 55mph .

But to enhance towing safety,
WDH made it feel more stable,
2off friction sway bars worked really well we don't feel semis passing us on the freeways anymore the TT feels heaps more stable.
Tuson Brake controller, enabled braking at any speed without the TT wheels locking up and the TT always feel as if its slowing the Tug (TV), never feels like the TT is pushing the tug.
Plus
The Tuson Electronic Sway control as the final guard, with a little modification mounting the LED diagnostic monitor on the tugs dash so the driver knows instantly if the ESC or brake system develops a fault when driving.

Worthwhile ...yes the cost when DIY is not a lot when its your families safety.

[RFV]

While we're on the subject, what's everyone's preference in name brand/type? Has anyone installed a setup on a vintage travel trailer?

[4X4Dodger]

To Stevec22:

I dont beleive the 5th wheel really has anything to do with it as trailers do sway that are attached to 5th wheels (doubles and Triples) because of the short distance between the pivot point and the axles and because as I said in my post the turning factor of the dolly.

And I have seen many a 5th wheeler TT going like mad swaying down the road.

And that really wasnt why I mentioned tractor trailers. I was using the tractor trailer comparison in regards to the weight ratio between the tow vehicle and the Trailer...because many seemed to indicate sway was a function of the tow vehicle weight vs trailer weight..

Your comment about speed is interesting. Generally while traveling forward with some pull, the trailer should not sway whether you are going 35 or 65. Its when you drive erratically, change lanes abruptly, brake without trailer brakes adjusted properly that you get the sway.

However if you really want to haul your TT at 70+mph then aerodynamics may come into it and you may experience some lift under the trailer which may induce some sway...where exactly that speed point is is different for every trailer I am sure. I do agree that speed certainly can be a factor.