Electronic Trailer Sway Control - How It Works - FCA

[Adventure.AS]

I have seen some questions arise on other threads about how TSC will help with trailer sway. This animation gives a good explanation (and also uses an Airstream tandem axle as the trailer in the rig.)

https://www.youtube.com/watch?v=UW64aRZgWu8

https://www.youtube.com/watch?v=w0RSLPBtCtw

[SteveSueMac]

Thanks for posting. I'm curious about how these work in real life. In my head (which is usually an inaccurate source of data [emoji3]) I have the notion that in a sway incident, there's a reason they tell us to manually apply the trailer brakes. I think that reason is to essentially "tighten the string".

Help me on the logic here. I think it works like this - If swaying, putting only the trailer brakes on will start to slow the trailer and if - at the same time - you not only don't apply tow vehicle brakes but actually give it a little gas, that "pulls the string tight" so to speak and straightens things out.

Does that sound even remotely accurate? Could be totally wrong so please correct if inaccurate.

Wondering if the auto braking of the tow vehicle helps or hurts that process. Or - do the manufacturers also suggest manually applying the trailer brakes when you feel sway?

[garry]

Putting on the TV brakes has the trailer pushing the TV since the TV slows down faster making the sway worse. Some controllers have a boost setting to apply the trailer brakes with greater force for a second or two that might stop the sway before it starts.
Using the controller manually has the trailer pulling back slowing both down at the same rate.
The electronic sway control would apply opposite side brakes from the sway direction controlling the pushing in the wrong direction.
However; that is just my guess fortunately I have never had a serious sway getting out of control to test the manual theory.

[dvgofaz]

I was on the highway Sunday morning and found myself behind an AS 25FB. I just followed for a few miles enjoying the view. I was really impressed by how solidly the trailer sat in the lane...zero sway, even when passed by big rigs.
As my exit was coming up I passed it so I could see the rest of the rig, it was a Chevy Silverado 1500 and a Hensley Hitch. I shoulda known.

[rmkrum]

Originally Posted by dvgofaz

I was on the highway Sunday morning and found myself behind an AS 25FB. I just followed for a few miles enjoying the view. I was really impressed by how solidly the trailer sat in the lane...zero sway, even when passed by big rigs.
As my exit was coming up I passed it so I could see the rest of the rig, it was a Chevy Silverado 1500 and a Hensley Hitch. I shoulda known.

As my High School Algebra teacher said a lot, "QED!"

That says it all...and Hensley design hitch performs like that--had to dodge a nice late model 27-footer pulled by a Nissan Titan using a Blue Ox hitch in Riverside, Ca area just yesterday.

Was a bit windy, and the AS was bouncing all over the place at freeway speeds. If the driver had been doing the posted 55 MPH limit (California) he might have done better. He was going fast enough we had trouble getting around him...not a great idea in those conditions towing a wide-body AS...

[vintagemotor]

I highly recommend the TSC as it applies the "correct" left and right braking to minimize the sway.
I have seen data that showed that the driver of the TV not even touching the brakes during a violent sway event and the Tuson slowed the vehicle combination over 40mph.
This device really works!

[jimfa440]

I agree with SteveSueMac. I started towing travel trailers in the very early 70's. My first was a 35' Concord travel trailer with a 4X8 tip-out (pre slide-out). I pulled it with a 1/2 ton Chevy. I quickly learned what semi trucks would do to me as they passed me. I figured out on my own that I needed to "tighten the string" as you put it. I would steer slightly to the right as the semi passed me while applying trailer brakes and throttle at the same time. I have been using that same process since.

[franklyfrank]

Originally Posted by jimfa440

I agree with SteveSueMac. I started towing travel trailers in the very early 70's. My first was a 35' Concord travel trailer with a 4X8 tip-out (pre slide-out). I pulled it with a 1/2 ton Chevy. I quickly learned what semi trucks would do to me as they passed me. I figured out on my own that I needed to "tighten the string" as you put it. I would steer slightly to the right as the semi passed me while applying trailer brakes and throttle at the same time. I have been using that same process since.

If you are concerned about semi truck buffeting you as they pass, simply let up on the accelerator before the semi pulls next to you. Than just before the nose gets even with the tail end of the trailer slightly accelerate while being passed. No need to apply the brake.
All these issues become pronounced when pulling with a marginal TV. You can't beat having a beefier TV for over safer towing.

[CMTampa]

Electronic sway control is a must have as far as I am concerned. My classic 30 came in before I replaced my Ram 1500. I thought it would be okay to take a short shake down trip with the small truck - big mistake. Semi passed shortly after I got on the interstate and the trailer sway took control of both vehicles. I didn't even think about manually applying the trailer brake before the electronic sway control kicked in and straightened things out and saved the day. White knuckled it all the rest of the way on back roads. I was at the dealer buying a new Ram 3500 and had a Pro Pride installed before the next trip.

[Abraham]

Another opinion on Electronic Sway Control

First, a disclaimer:

1. I don’t have a vehicle with Electronic SWC system.
2. I don’t have a ProPride/Hensley WDH
3. I do understand the High School physics that explains both of them.
4. I have experienced violent wind induced trailer sway.(twice).
5. I have towed several different AS’s with several different TV’s over 30 years and many miles of various road conditions, including mountains.

Tightening the string is the way to stop sway, even in the Electronic systems.
However, without including the trailer brakes in the “electronic’ system, it is of limited benefit and will not work well in violent misalignment of the trailer/TV.
High school physics, again.

Tightening the string, from either end helps, but doing it from both, gets the job done much better. And applying differential braking on the TV just doesn’t do enough in extreme situations.

I will agree that ProPride/Hensley WDH systems have notable advantages in sway control, they also have some disadvantages, like 80 extra pounds of hitch weight, (Check your max hitch load / max payload capacity for your own situation) and are a bit more difficult to set up each time you hitch. I use a Reese WD hitch with ‘Dual Cam Sway Control;’ and find it very satisfactory.
(Just for the record; I don’t like friction sway control bars. A discussion for another time.)

As for the previously mentioned sway events, one time a violent gust pushed my 31 ft. AS completely across the next lane of the highway (fortunately unoccupied at the time): full trailer brakes and full throttle on the TV is the ONLY thing that saved the equipment. Needless to way, I reduced speed for the rest of the way to a safe place to stop and wait out the weather. Fortunately, the TV was a ¾ ton truck with a big enough engine to do the job well. I have a definite preference for ¾ ton trucks for TV with most trailers of more than about 3500 pounds, no matter what the manufacturer of the TV suggests.
Maybe overkill, but high school physics still tells me that a heavier TV helps with control.

In the recent past, I used a GMC Sierra 1500 TV for my 25 ft. 6500 pound AS.
It did the Job, but did not inspire the confidence that I now enjoy with my Chevy 2500 HD, with Duramax Diesel. Again, it may be overkill, but I like it.
(Still own the GMC and use it for other things.)

Take care and enjoy safe travels.

[JCWDCW]

Originally Posted by SteveSueMac

Thanks for posting. I'm curious about how these work in real life. In my head (which is usually an inaccurate source of data [emoji3]) I have the notion that in a sway incident, there's a reason they tell us to manually apply the trailer brakes. I think that reason is to essentially "tighten the string".

Does that sound even remotely accurate? Could be totally wrong so please correct if inaccurate.

Wondering if the auto braking of the tow vehicle helps or hurts that process. Or - do the manufacturers also suggest manually applying the trailer brakes when you feel sway?

Experience with an Award trailer and 1500 size Jimmy years ago confirms your assumption. 23 ft Award was known to be a sway machine. Most people ran with TWO friction controls.
I could settle the trailer down by accelerating....but going down hill, where the problem usually occurred, that was not an option as hitting the bottom at high speed was not good either. If I touched the manual activator the trailer straightened out and settled down. Quickly made arrangements to install the friction bar anti-sway.
The automatic system is programmed into the TV computer controls; it can't apply trailer brakes since it is not programmed to do so.

Interesting comments about truck interference. My truck tends to head left as a truck encounters the trailer and I need to steer away from the truck, since the whole trailer truck string is fairly rigid and the trailer gets pushed to the right. I had the same experience with my previous Hensley Hitch. Surprising how often I get Beeped buy the passing truck who thinks I'm headed into his lane, and usually by some driver who is running on the lane divider line. I have only once been sucked into the passing truck by both vehicles being too close... Venturi effect...takes some fast reactions to get out of it. Brake and steer away
JCW

[Asherstanton]

I had TSC on a rig in Australia. Different application than here. I went to their booth at an RV show in Brisbane expecting to hear that it used differential braking (one side of the trailer or the other). Nope. They said they tested it and they just apply all the trailer brakes at once. Said it worked just as well. I never had a problem with it. In Australia sway might induced more from some of the hideous roads we used (no not all of them are bad). This is just an FYI FWIW. They had some impressive videos you might be able to find. It was about $1200 Australian which would be considerably less in exchange. Don’t know if you can get it sent over. It’s Alko ESC. Here’s an article comparing it with Dexter sway control you might find interesting. Remember in Australia and GB a TT is called a caravan. https://www.caravanworld.com.au/feat...ol-system-test

[switz]

Tuson has a system now where the trailer brake wiring is modified so that their brake controller mounted in the trailer can apply one side or the other trailer brakes for sway control.

Their best system involves disc brakes and ABS.

[RTOS_LLC]

The Tuson electronic sway controller is not like putting on the brakes and making things worse. When the trailer sways left it applies the left brake only, when it sways right it applies the right brake only. The faster trailer sways, the harder the brakes are applied. Power is drawn from the trailer battery, and thus reacts very quickly versus a human as a sensor is constantly monitoring for sway. If you apply brakes (blue wire) the sway control pulses "add" to the blue wire signal, unless of course the blue wire pulses plus the sway pulse exceed a 100% blue wire pulse. It does a lot more than this, but this is why the Tuson system works and that "other" electronic sway controller does not work.