Sway. Before, during and after.

[Vitaver]

Sway, how to prevent it, what to do when it gets past comfort level and what to do immediately if results in disaster is a topic that certainly was addressed in many threads and will be a major endeavor to collect them all, so I hope we can start a discussion strictly limited to the 3 items at the top. Hard to imagine anyone towing, no matter for how long (12 years in my case), is not preoccupied with any of the three topics, so let’s give it a try to help each other and newbies.

Sway happens... It does result on catastrophe many times a year. It is an important topic no matter what TV, TT or hitch is used yet our collective experience and research may help us all. I‘ll post one for each following this, to initiate the conversation on this chat. Thanks to all who take an interest and chose to contribute.

Checking tyre pressures, safety brake connected at both ends and 7 way connector providing power to the TT are understood.

[Vitaver]

Understanding that a correct match exist between TV and TT, the connecting point will be the hitch. There is almost a cult following to some brands and it would be beneficial to know the advantages/weaknesses of each from those with experience in them, especially if earned using different kinds. Do you have a predilection and if so, why? Do you abhor (or simply avoid) another? Why?

[Vitaver]

Comfort level varies, interesting is when it crossed yours. What do you do to bring the rig to a straight line in the lane you follow?

Some suggest just letting go of the gas and quickly add, don’t step on the brakes. We can probably all agree on that, but what do do the next seconds when that is not enough?

Manually actuate the brakes on the TT while stepping on the gas?

[Dennis C]

I received advice from my Airstream dealer when I bought my trailer on how to deal with sway. His suggestion was to let off the accelerator, then to quickly pulse the trailer brakes using the brake controller. He told me that hitting the brakes in the tow vehicle isn’t the best response, even though it’s many people’s first instinct. Fortunately, I’ve never had any sway issues while towing my Airstream or any other trailer. I’ve never been able to test this method. My truck has automatic electronic anti-sway control, but I don’t think that has ever been activated.

[Vitaver]

If you are lucky or expert enough that never had an accident with the TV/TT combo, glad for you and may the Highway Gods always be with you!

Others have not been so lucky and... you can take my word for it, instinct alone is not always enough. It is surprising how idiotic the reactions of a person startled by an accident will be (E.j. Me).

Developing mental and muscle memory are, IMHO essential to react on time and correctly to the emotional stress of an adverse event we did not anticipate. (Check the reaction of a cop, if you dare, by just reaching to your back pocket to grab your handkerchief while talking with one. I did, he did not pull a weapon on me but his hand ran behind him ready to pull ‘something’, getting there even before mine (I initiated the move) reached my hanky). That is the result of obsessive drilling, necessary for LE to survive. We probably need the same ‘automatic’ reaction to, for instance, exaggerated sway and initial loss of control. Even more if an accident results.

Knowing what to do, is not enough. Practice/drilling is necessary as there is no time to remember or think what to do. Agree? Ideas?

BTW, Coachnet is useless. I can say this with authority, I called on them twice for a minor and a major event. All they did is ask tons of questions culminating on ‘why can’t help you on that’. Just delayed positive action to cure the situation!

[Daquenzer]

1. I use a Propride no sway hitch. It is expensive, but it works wonderfully. Advantages: Easy to adjust Weight Distribution, design is created to prevent sway before it starts. Disadvantages: heavy on the tongue, expensive, requires more maintenance.
I have used Blue Ox. Not expensive, Lots of bow affect from trucks, easy to maintain, hard to adjust with chains,
2. In sway situation: slow down (foot off gas don’t break with TV), slight to modest application of trailer brakes with brake controller until the truck and trailer align.

[ROBERT CROSS]

We have only been "Streaming" since '87.
With our first...I did NOT take my foot off the gas, maintain and applied AS brakes.👍

In 2007 we installed a Hensley Arrow on "Cloudsplitter", we haven't 'swayed' since.


Bob
🇺🇸

[Vitaver]

Originally Posted by Daquenzer

1. I use a Propride no sway hitch. It is expensive, but it works wonderfully. Advantages: Easy to adjust Weight Distribution, design is created to prevent sway before it starts. Disadvantages: heavy on the tongue, expensive, requires more maintenance.
I have used Blue Ox. Not expensive, Lots of bow affect from trucks, easy to maintain, hard to adjust with chains,
2. In sway situation: slow down (foot off gas don’t break with TV), slight to modest application of trailer brakes with brake controller until the truck and trailer align.

Yes about the bow effect with Blue Ox, every time. As for adjusting with chains the solution (for me) has been to raise the jack all the way, even lifting the bed of the truck, not the tires from the ground though. At that point there is no effort to hook or unhook the chains, but the bow effect is bad enough that trumps any easy of hooking it. My last trip with a Blue Ox Swaypro was quite bad...

[Vitaver]

Originally Posted by ROBERT CROSS

We have only been "Streaming" since '87.
With our first...I did NOT take my foot off the gas, maintain and applied AS brakes.👍

In 2007 we installed a Hensley Arrow on "Cloudsplitter", we haven't 'swayed' since.


Bob
🇺🇸

Did ProPride buy Hensley out or they remain independent companies/products?

Can you please give us some more info on the Arrow, ease to install, hook, dial, etc?

[rmkrum]

ProPride manufacturers Jim Hensley’s latest design. IMHO greatly improved over Hensley Manufacturing’s product which is Jim’s original design.

Either of them use similar methods for preventing sway, the difference is in the installation method, the size and durability of the components, and the price. I also found customer service with ProPride conformed to my expectations. Superb support and willingness to answer questions quickly.

I went with the ProPride system because it does not require any drilling holes for bolts onto the A-frame, has an adjustable stinger, and in general is very heavy duty.

My setup has custom powered WD jacks, because I’m getting old and tired, and putative head of the legendary Overkill Engineering Department. These are special made one-off items and not available commercially. All I do is hit a switch to tension my WD bars.

[BayouBiker]

Since this is intended to be a detailed thread on sway, it may be helpful to formally define it, and describe what are the causes and what contributes and enhances the effect once it starts.

Trailer sway or fishtailing is a side to side oscillation initiated first by a lateral force acting on the trailer causing the tongue to accelerate sideways and inducing yaw in the trailer (the trailer now slips sideways pulled by the tow vehicle in its direction and not in the direction the trailer is pointing. At this point the tow vehicle experienced some degree of oversteer so it too is experiencing yaw in the opposite direction as the trailer. That sets up a negative feedback response to eliminate yaw as the natural state is no yaw in either vehicle. If yaw damping is insufficient for any number of reasons, the feedback response will be too great and the tongue will overshoot and fly past the natural steady state position setting up yaw the opposite way. If the system is undamped, yaw amplitude will remain the same in both directions and the combination will fishtail endlessly down the road. If it critically damped, the system will not oscillate at all, instead it will go to one side in response to the force and then harmlessly return to the natural state. If it underdamped it will oscillate with diminishing amplitude until it dies out. However if it is unstable, amplitude will grow with each oscillation until the combination critically oversteers, jackknifes and rolls.

[Vitaver]

I read and re-read your posting and find it very educational, a bit over my head I am afraid though but what you described as chain of events actually happened to me recently and did not ended up well. No blood was spilled though. Now two questions please:

1. What, other than strong wind (there was none) could have initiated the sway? No rapid lane changes, change in speed or bad tires on the TT, yet one rear tire on the TV was 10 PSI under, when checked after the ‘situation’.

2. Please share the name of the hitch you chose as best. Please.

[Daquenzer]

Originally Posted by Vitaver

Yes about the bow effect with Blue Ox, every time. As for adjusting with chains the solution (for me) has been to raise the jack all the way, even lifting the bed of the truck, not the tires from the ground though. At that point there is no effort to hook or unhook the chains, but the bow effect is bad enough that trumps any easy of hooking it. My last trip with a Blue Ox Swaypro was quite bad...

A couple of things that might help with your Blue Ox. It seems you should be able to get a good towing experience with a 19’ with the Blue Ox.
1) Try putting roadmaster suspension system on your F150. That will stabilize suspension of your F150 which has a tendency to porpoise. Cost is about 650 installed.
2) Get stiffer side-wall tires.

Even if you get a different hitch these things will help stabilize. I have 20 inch tires on my F150 which helps. And I also have the roadmaster suspension system.

They do make a smaller Hensley Hitch for the smaller trailers called the Hensley Cub.

And I did the same thing you did with installing the chains. I just didn’t like messing with the chains. The nice thing with the weight distribution on the Propride or Hensley is how easy it is to adjust. So if I’m towing and I don’t like how the truck is handling I can adjust very easily up or down without disconnecting anything.

All I can say is that after installing the Propride it is so much more enjoyable to drive; especially on roads with heavy truck traffic.

[OTRA15]

Originally Posted by Vitaver

. . .
Manually actuate the brakes on the TT . . . ?

Yes.

Most sway events can be anticipated if one is "situation-aware," which includes being wide awake, and paying very careful attention to all possible risks. These include wind gusts, semi trailer bow waves, and so forth.

If you are tired, sleep-deprived, a victim of self-inflicted "gotta-get-there-itis," or under the influence of drugs or alcohol, etc. . . .
[edit -- plus loud music, blabbing on the cell phone, arguing with others, etc.]

. . . you may have set yourself up for a fall IMO.

A careful driver usually sees the risks building ahead of time!

Especially with a semi trailer bow wave [either coming at you on a two-lane road -- or parallel to you on a divided highway], you must already have one hand on the manual brake controller, ready to apply the trailer brakes first. If this is done correctly, there should be no need to step on the gas also IMO.

"Every-minute Zen!" [hot link]

[OTRA15]

PS -- A poor hitch/sway set-up "pre-loads" the risks against you, of course . . . beyond my knowledge base to comment any further on this factor. [edit -- plus tire pressure etc. issues]

Re: Every-Minute Zen:

https://www.amazon.com/Zen-Flesh-Bon...2692458&sr=8-1
____________________________________________

“Zen students are with their masters for at least ten years before they presume to teach others. Nan-in was visited by Tenno, who, having passed his apprenticeship, had become a teacher. The day happened to be rainy, so Tenno wore wooden clogs and carried an umbrella. After greeting him Nan-in remarked: ‘I suppose you left your wooden clogs in the vestibule. I want to know if your umbrella is on the right or left side of the clogs.’

Tenno, confused, had no instant answer. He realised that he was unable to carry his Zen every minute. He became Nan-in’s pupil, and studied six more years to accomplish his every-minute Zen.”
______________________________________________




FWIW!

[smithcreek]

Fifteen posts and no mention of "CAT scales"? I don't have experience with anything but my Reese Straight Line, but I would guess most all hitches work well enough when you load the trailer and set up the hitch properly. Just cranking more tension into the chains is not how you get rid of sway.

[B. Cole]

Originally Posted by Vitaver

I read and re-read your posting and find it very educational, a bit over my head I am afraid though but what you described as chain of events actually happened to me recently and did not ended up well. No blood was spilled though. Now two questions please:

1. What, other than strong wind (there was none) could have initiated the sway? No rapid lane changes, change in speed or bad tires on the TT, yet one rear tire on the TV was 10 PSI under, when checked after the ‘situation’.

2. Please share the name of the hitch you chose as best. Please.

#1-Keep weight in front of trailer axles, not behind axles.Especially a single axle.That means dumping tanks/ moving weight forward/ etc prior to towing.etc.
# 2-Tow with a heavy / long wheel base tow vehicle, that is suitable for the job. ( not overpowered/ driven by trailer).
An example of #2 would be, a F-350 or F-250 instead of a F-150.
Another example of #2, of what not to do, is inexperienced towing people, who put expensive / heavy hitch set ups ( with sometimes lots of expert advice), on little / sporty/ short wheelbase SUVs, like a Jeep/ LandRover/ Porsche etc etc etc type rigs II ( the list is endless) and attempt to pull trailers too large/ way too large/ for said baby SUV Tow Vehicle.
Heres even more help, for those new to towing Airstreams ( in this forums case).
A SUV, is, by definition, a SPORT UTILITY VEHICLE.
If used for towing, they should ideally and for safety, be matched with and towing only small ( like the SUV is) UTILITY trailers, like a little lawn trailer, or rowboat trailer/ etc etc.
Trucks are for real towing.
The bigger, the better.
Heres a real world towing example of how that works, if needed. Lets say A SUV towing a too large trailer, sways and flips/wrecks.Or can't stop safely and also wrecks.Etc etc
A tow truck arriving on the accident scene,( Wrecker) doesn't need a WDH/Anti Sway Hitch.
A 2 +5/16 " (Bumper pull) Ball is sometimes stuck on the back, and trailer needing towed is dropped on the ball.
Away it goes.
Glad to help....

[BayouBiker]

Originally Posted by Vitaver

I read and re-read your posting and find it very educational, a bit over my head I am afraid though but what you described as chain of events actually happened to me recently and did not ended up well. No blood was spilled though. Now two questions please:

1. What, other than strong wind (there was none) could have initiated the sway? No rapid lane changes, change in speed or bad tires on the TT, yet one rear tire on the TV was 10 PSI under, when checked after the ‘situation’.

2. Please share the name of the hitch you chose as best. Please.

From the description of sway, we can readily see the primary cause of sway for any combination that experiences it as too little yaw damping for the particular conditions at the time sway occurred. So anything that reduces yaw damping or increases the need for additional damping can cause sway. What is yaw damping? It is anything that acts to resist changes in vehicle and trailer yaw angles, and recall that yaw is the difference between the direction of the vehicle or trailer and the direction it is pointing. A vehicle or trailer with yaw is slipping sideways a bit. This does not mean the tires have lost traction with the road and are skidding because lateral stress on tires flexes the sidewalls and distorts the footprint sideways a bit so the tires won't travel exactly in the direction they are pointing. This difference in angle is the tire slip angle.

OK so what are common sources and influences to yaw damping?

1. Trailer loading

1a. Trailers with large relative inertial moments (weight evenly dispersed lengthwise) like Airstream travel trailers require more damping than a utility trailer or a boat trailer who's weight is more concentrated near the axles. This is because it takes much more force resist the inertia of the dispersed weight.

1b. moving the center of gravity forward of the axles greatly increases trailer yaw damping by separating the location of lateral resistance (the axle) from the pulling force and the forward inertia which acts through the center of gravity. The further forward COG is the greater are the forces for trailer inertia to self stabilize and eliminate trailer yaw. Thus a trailer with 15% tongue weight is far more stable against trailer yaw than a trailer with 10% tongue weight.

2. Towing Speed

All the forces acting to maintain and increase vehicle and trailer yaw are proportional to the system relative kinetic energy or velocity squared. Thus a doubling of speed increases the need for more yaw damping by a factor of four. Trailers are generally designed to be inherently stable at 55 mph or greater when properly loaded. Travel trailers with 10% tongue weight will be stable at about 55-58 mph and about 68-70 at 15% tongue weight. Higher tongue weights are more stable for sway but cause severe oversteer instability if tongue weight is excessive, so there is a tradeoff.

3. Tow vehicle vs. Trailer inertial moments

The trailer and tow vehicle wrestle for dominance. If the trailer inertia is greater than the vehicle inertia, the trailer is capable of pushing the vehicle around and much more yaw damping is required to keep the combination stable. Vehicle inertia is influenced by vehicle loaded weight and wheelbase. Short light tow vehicles towing trailers longer and heavier than the vehicles require significant damping measures.

4. Tow Vehicle vs. Trailer tire slip

High trailer tire slip (low cornering stiffness) allows the trailer to sideslip more easily and exert less force on the tow vehicle that would induce yaw in the vehicle. Thus sway feedback coupling is reduced, effectively increasing yaw damping. Likewise, high vehicle rear axle cornering stiffness has the same effect.

5. Hitch anti-sway damping

Anti-sway hitches introduce resistance to yaw by resisting angular changes at the ball and tongue joint. Some have much more damping resistance than others. The Hensley designs have the most by far.

6. Anti-sway controllers

Anti-sway controllers asymmetrically apply brakes to greatly increase yaw damping and arrest sway tendency.

7. Dynamic forces

Rapid deceleration unloads vehicle rear axles and greatly diminishes tire stiffness so sudden removal of engine power or applying brakes at the wrong time can induce sway very suddenly

Cross Winds - Especially variable, Yeah this should be obvious

Semi Tractor and other large vehicle slip streams

Sudden swerves

All of these will temporarily and dramatically increase need for yaw damping.

[DCPAS]

Originally Posted by BayouBiker

OK so what are common sources and influences to yaw damping?

Brian: I think you are missing damping provided by modern tow vehicles. Mine (a maligned in this thread SUV) provides two types. One is differential braking and the other is torque vectoring using an electronic limited slip device.

[BayouBiker]

Point 6 addresses sway controllers. They are quite effective at arresting sway and can help with oversteer to a lesser degree, but they are no substitute for the inertial moment of heft and wheelbase. I am continuously surprised by those who want to bring knives, even fancy ones to a gunfight.... Alas, what is a poor boy to do?