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Although not described in the prior videos is a common scenario where too heavy of a tongue weight pushing down on the rear of the tow vehicle reduces the weight on the front tires of the tow vehicle, which also increases the sensitivity to a sway event and reduces the ability to steer the tow vehicle due to lack of traction on the front tires.

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What does a weight distribution hitch do?  The following is an excellent weight distribution hitch operation explanation and hopefully explains when and why a weight distribution hitch is needed and how an adjustable hitch helps distribute the tongue weight properly between the front and rear axles of the tow vehicle.

The information you need to enter into the software tool provided by the prior hitch vendor, to determine the desired tongue weight for your trailer, includes the following data.

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  • Estimated Gross Trailer Weight

  • Tongue Weight

  • Rear Vehicle Axle Center-line to Tow Ball (inches)

  • Tow Ball to Spring Bar Connection (inches)

  • Tow Ball to Center-line of Trailer Axle(s)

 

Once you collect the above data you can then enter your values into the on line calculator which follows to determine the recommended tongue weight.

To determine the actual tongue weight on your trailer, to facilitate adjusting it properly without a hitch similar to the one referenced above, includes first determining the tongue weight with trailer loaded as if you were taking a trip by either;

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  • purchasing a device intended for this purpose,

  • driving to a location containing a scale and measuring the rear axle weight of tow vehicle with trailer connected and disconnected, or

  • optionally follow one approach utilizing a household scale to determine tongue weight.

Once your tongue weight is known, now follow the directions for your weight distribution hitch, if available.

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Once you have a proper distribution of the weights across the tow vehicles front and rear axles, as well as trailer axles, the sensitivity to a sway event due to improper loading is now reduced.  However, having a properly adjusted weight distribution hitch does not eliminate the possibility of a sway event but reduces the likelihood of a sway event occurring due to improper loading.  When subjected to a wind gust or an evasive maneuver you may still get a sway event which is where a quality electronic sway controller can significantly reduce and stop the sway event by applying the left and/or right trailer brakes to offset the sway energy.

 

The following electronic sway controller provides asymmetric sway control (individual application of left and/or right brakes) for sway levels beyond those that can be reduced with a properly adjusted load leveling hitch.

The following is a long video (28 minutes) performing various levels of sway performed on a test track.  In this video two sway controllers exist, one within the tow vehicle itself and a Tuson Sway Controller on the trailer.  Tests are performed by; 1) enabling only the truck sway control, 2) enabling only the Tuson Sway Controller, 3) enabling both sway controllers, 4) no sway controllers, and 5) changing tongue weights from correct loading to nearly no tongue weight.  While each test is performed this video includes reactions by the driver and passenger during each sway event.

As demonstrated in the prior video an asymmetric sway controller stops sway even during a worst case test scenarios with minimal tongue weight and evasive maneuvers!  This does not imply that proper trailer loading, proper tongue weight adjustments and load leveling hitches are not required, since constant application of left and right brakes by an electronic sway controller would eventually overheat the trailer brakes and then sway would resume.  As long as you have a properly adjusted load leveling hitch, operational trailer brakes and an operational asymmetric sway controller your likelihood of a large sway event is significantly reduced.  This is why insurance companies in Australia provide an insurance discount when a sway controller is installed on the trailer. 

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Since our goal was to educate the consumer we will also include descriptions of less effective means of reducing trailer sway, specifically using electronic sway controllers that only apply “all trailer brakes” when a sway event is detected, which effectively just slows down the vehicle and thus reduces sway.  If this was the best way to reduce sway your tow vehicle’s stability control system would apply all vehicle brakes, but instead individually applies individual vehicle brakes at specific braking levels at specific times as it is the only approach that works.

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The only comparison we could find that compares an asymmetric sway controller with a symmetric controller, which activates all brakes, is the following document which compares the AL-KO ESC versus Dexter (Tuson) sway controller;

Since we were unable to find any technical explanations of the differences between Symmetric and Asymmetric Trailer Sway Control we created the follwoing explanation relative to why asymmetric sway control can generate forces to actually reduce trailer sway and why symmetric sway control can only slow the trailer and tow vehicle to reduce sway.  Test results run by Ford Motor Company to verify compatability with Ford Sway Control System is also provided.

All known tow vehicle stability control systems individually control each vehicle brake to maintain control of the tow vehicle.  All trailer sway controllers, other than the Tuson Sway Controller, activate all trailer brakes when a sway event occurs which therefore are far less effective than the asymmetric sway control approach.  The following Dexter video is one of the better descriptions on the operation of asymmetric sway control:

A short explanation of the installation wiring of an asymmetric sway controller:

In Australia sway controllers are either ordered as a trailer option or installed by a service center although a competent Do It Yourself (DIY) individual can easily perform this installation themselves.  The following is an installation video for a Tuson Sway Controller:

Perhaps the most relevant video is a testimonial of a customer whom had an asymmetric sway controller installed on their trailer and how it affected their trailer towing experience:

CONCLUSIONS:  If towing your trailer on a windy day or passing trucks on the highway gives you white knuckles please consider the following to improve your driving experience.  A weight distribution hitch, when adjusted properly, distributes the recommended trailer tongue weight to reduce the likelihood of a sway event “due to improper tongue weight” under normal driving conditions.  If your tongue weight is not correct when your trailer is loaded you should very seriously consider a weight distribution hitch to resolve this issue.  When a sway event occurs due to wind gusts or evasive maneuvers of the driver the asymmetric sway controller individually activates left and/or right brakes and significantly reduces the trailer sway.  Although an electronic asymmetric sway controller reduces sway for an improperly loaded trailer by activating the trailer brakes to do so, it is not intended to be a substitute for proper trailer loading and will only work properly if the trailer brakes are operational.  A combination of a weight distribution hitch and an asymmetric sway controller is highly recommended.  If your tongue weight is correct without the use of a weight distribution hitch then an asymmetric sway controller is recommended.

TRAILER SWAY TUITORIAL

It is difficult to make wise purchase decisions without understanding the benefits of the various trailer towing and braking products.  If you have experienced “white knuckles” while towing a trailer on a windy day, or have rolled you vehicle during a sway event, the following attempts to provide what occurs during a sway and how prevent it.  The following information attempts to answer the following;

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  • How does trailer tongue weight affect sensitivity to a sway event

  • What not to do during a sway event

  • What does a weight distribution hitch do and how to adjust it

  • What does an electronic sway controller do to reduce sway

  • Electronic sway control customer testimonial

 

Having navigated the web for content that can be understood by the “normal human being” RTOS is providing a collection of references that we feel best explain the functionality provided by weight distribution hitches and electronic sway controllers.  Our primary goal is to help educate the consumer utilizing existing web content, while trying not to endorse any specific products but explaining why utilizing each type of product will improve your trailer towing experience.  From their accents you will note that many of the following videos are from Australia, as they have been utilizing electronic sway control devices for many years and where their insurance companies actually provide insurance discounts when an electronic sway controller is installed on their trailers.

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The first video contains a trailer sway crash video when passing a truck in Australia and then demonstrates a “simulated sway event” caused by improper tongue weight and how improper trailer loading affects sway sensitivity.

The prior video demonstrated how a low tongue weight will result in greater sway and where a proper tongue weight will reduce the sensitivity to a sway event.

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The second tongue weight video uses a toy hauler analogy and is similar to the prior video but introduces the 10-15% tongue weight concept.

Although it may not be obvious from the prior videos a sway event is often referred to as “the tail wagging the dog”.  When a trailer sways left the tongue pushes the rear of the tow vehicle to the right and when swaying right pushes rear of tow vehicle to the left.  The lower the tongue weight the easier it is to push the rear of the tow vehicle left and right.

 

What NOT to do during a trailer sway event is described in the following short article which includes some intuitive pictures.

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