Trailer sway

U-Haul has put together a trade show demonstration to illustrate the effect of trailer loading on handling. Jalopnik says you can Learn About The Dangers Of Towing From A Toy Mustang On A Conveyer Belt. See the short video.

This is even likely less bad than a full-scale, real-world situation would be, because that conveyer belt is going at a steady, constant speed, and the car’s front wheels remain rigidly straight. In reality, once the swinging starts, the Mustang driver would likely be alternating cranking the wheel in a panic while jamming on the brakes, taking some time between these two acts to lavishly soil their pants.

So, take it from some toys on a conveyer belt: be careful how you distribute the weight of what you tow!

The steering issue needs emphasis as well. Because of the sideways push on the rear of the tow vehicle, oversteer (wikipedia) is common. That means that corrections to compensate for the trailer wiggle tend to produce more steering than intended. That means a correction to the correction is needed and that is what is called a positive feedback loop (wikipedia). That’s the source of oscillations and the last thing you want with trailer sway is an oscillation.

The video emphasizes that the first step in effective trailer handling lies in proper trailer configuration and loading. This is why Airstream has its water and holding tanks low down and near the axles. It is also why Airstream tends to have longer axle to hitch distances than many other trailers. The load distribution in the trailer involves the interior design as well because that determines the location of heavier objects (like the appliances) and the storage lockers. 

Tow vehicle loading, suspension, and configuration are also a part of the equation. That influences steering and the vehicle response to disturbances. Effective handling is not a simple phenomena. There is much you can do to make for a comfortable driving experience but you also need to be aware that training and experience are needed and that road and environmental conditions can bring surprises. 

Take care. Drive aware. Be prepared.

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