This is not an optical illusion

Thanks! That makes sense. Same reason dry vans will collapse if something crazy is loaded.
I guess I just assumed having a support beam would make that concern irrelevant, never considered the limitations of engineering.

 

Not long ago, nothing had a rating. Spools, side rails, trailers. It was up to you to buy a trailer and use it accordingly. If it didn't do the job, you added crossmembers, strapped the frame, re arch it every few years, put heavier suspension under it

Very limited warranty and dependant on operator to have half a brain. Now its cookie cutter trucks and trailers.

 

I've seen my trailer move side to side like a snake while taking sweeping turns or semi-sharp lane changes. Always freaks me out. You can actually see a slight wave to it when standing behind it and it's unloaded. It's a Great Dane too.

 

[QUOyes and TE="ProfessionalNoticer, post: 11604280, member: 317301"]I've seen my trailer move side to side like a snake while taking sweeping turns or semi-sharp lane changes. Always freaks me out. You can actually see a slight wave to it when standing behind it and it's unloaded. It's a Great Dane too.[/QUOTE]
And yet a couple hundred dollars and 150 added pounds it can be minimized. X-bracing behind the fifth wheel plate, dolly legs and ahead of the front axle on a spread or at the start of the slider on a tandem. the X-bracing should be bolted to the cross members at the inside of the frame and cross 3rd or 4th crossmembers and then bolted at the inside of the 6th or 8th at the frame. Then the same for the other X braces. Z strapping between the X's or more X's completes the stiffening. All the strapping should be 1.5"X1/4" flat bar and bolted at least every second crossmember and 1/4" grade 8 bolts will be strong enough. The company I worked for in the 90's did this to all their lightweight Wilson 48' flat trailers.

 

And yet a couple hundred dollars and 150 added pounds it can be minimized. X-bracing behind the fifth wheel plate, dolly legs and ahead of the front axle on a spread or at the start of the slider on a tandem. the X-bracing should be bolted to the cross members at the inside of the frame and cross 3rd or 4th crossmembers and then bolted at the inside of the 6th or 8th at the frame. Then the same for the other X braces. Z strapping between the X's or more X's completes the stiffening. All the strapping should be 1.5"X1/4" flat bar and bolted at least every second crossmember and 1/4" grade 8 bolts will be strong enough. The company I worked for in the 90's did this to all their lightweight Wilson 48' flat trailers.[/QUOTE]

I'll talk to my trailer shop about possibly having it done. Never heard of it personally. Is it called, "strapping"?

 

[/QUOTE]I'll talk to my trailer shop about possibly having it done. Never heard of it personally. Is it called, "strapping"?[/QUOTE]
It is just 1.5"X1/4" flat bar usually sold in 20ft lengths that is used as strapping materiel.
Spend some quality time on your knees with a tape measure planning your X-bracing to figure out how much to buy.

 

Gees, what kind of equipment are you guys running? It sounds like you are trying to make something I to something it wasn't intended to be.

 

I'm not changing, nor adding anything to the trailer. I thought about it at first but after talking to my trailer shop they said it's meant to flex instead of being stiff and rigid. As long as it's loaded properly and structurally sound there should be no issues.

 

"structurally sound" is the main thing here. I guess you could ask how much side sway should be expected with a concentrated load in the middle if the trailer.
"Loaded properly" is the other thing, you might want to ask how you load those concentrated loads to prevent side sway.

 

My spread is always properly loaded.