Extreme trailer sway leads to crash - GIF

[Altair]

Extreme trailer sway leads to crash.




Previously:

Truck swerving while being towed - GIF
Trailer towing swerve recovery - GIF
Overloaded trailer fail - GIF
Trailer of cattle almost tips over - GIF
Towing weight distribution display

[Karl_H]

Here is a nice demonstration of what happens and how to avoid it - no explanation of why it happens this way.

[mansworld]

The most common cause of sway are gusts of wind, or in this case, drafts from passing vehicles.

[NortonDommi]

The most common cause of sway are gusts of wind, or in this case, drafts from passing vehicles.

Also incorrect loading No.1, stupid driving No.2. I don't know why but many people commit crazy passing maneuvers and speed when towing a trailer. The same idiot mentality that makes people tailgate when it rains.

[old kodger]

I note with interest that the vehicle taking the footage didn't stop to see if they could help with anything.
Not my problem Jack, pull up the ladder.

[Toolmaker51]

I note with interest that the vehicle taking the footage didn't stop to see if they could help with anything.
Not my problem Jack, pull up the ladder.

Didn't stop, not even appearing to back off speed or veer one fraction in avoidance. The swerving truck didn't have much time to react, no evidence of brake lights or effort to slow and lessen fishtailing. It seems just a load of wood; I'll bet it's a tilt trailer, takes planning to get tongue weight. Uniform full length items will balance behind the axle, sway included free.
I've only had one load act up, a 36" Moak Bandsaw, it must be over 8' tall, giant 5hp direct drive, table removed to ship, whole frame is cast iron. Estimating the center of gravity (to right side of axles) wasn't enough. Soon after entering highway, she started acting up. So, broke down the ratchet straps, and used them to pull load farther forward, with a tape measure to judge height of hitch.
Needed more than a foot to get it right.
Rest of the drive uneventful.

[Karl_H]

... pull load farther forward, with a tape measure to judge height of hitch.

What parameters did you use? I can see that the hitch higher than baseline (baseline being no trailer attached) would indicate that the load is too far behind the trailer axle; hitch way lower than baseline, the load is too far forward. Is there a spot where it is just right, or did you do a trial and error and use the height as an arbitrary increment?

[Tooler2]

What parameters did you use? I can see that the hitch higher than baseline (baseline being no trailer attached) would indicate that the load is too far behind the trailer axle; hitch way lower than baseline, the load is too far forward. Is there a spot where it is just right, or did you do a trial and error and use the height as an arbitrary increment?

I load till I see tow vehicle go down a bit.

[Tooler2]

This was a case of driver incompetance, he tried to steer out of the problem instead of simply slowing down. The tow vehicle was plenty heavy enough for the load.