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Originally Posted by yogiyoda
I did find this thread on conventional fifth wheels. A few posters comment on how going much lower than 20% pin weight is not good. Complaints are of worsened handling and the risk of "porpoising" and that things can "get scary".
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I think the problems people have with fifth-wheels are typically due to height: big conventional fifth-wheels are very tall, substantially taller than conventional trailers of the same size. Of course, this is to some extent a problem for an Escape 5.0 or 5.0TA as well, as they are taller than the conventional Escape models to provide enough vertical space in the sleeping loft. Pitch oscillations ("porpoising") may suggest a height issue. It's not obvious to me how high hitch weight would help this, but perhaps getting some load off of the crude trailer suspension and on to the truck's suspension helps, if only due to the truck suspension's much better damping.
Another pair of related problems are trailer length and weight - the length of the bodies of the
smallest conventional fifth-wheels are almost as long as the bodies of the
longest conventional travel trailers (although "park models" can be longer). They typically weigh about twice as much as the tug. I'm sure that there are stability issues with fifth-wheels, but the biggest conventional trailers are serious challenges.
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Originally Posted by yogiyoda
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Given the content of posts in that discussion, it is clearly not the place to go for any useful information. It starts with a semi truck driver who doesn't know what "semi" means...
This comment
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I would not add to much weight to the rear or you may get a rig that will have a tendency to poripose.
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suggests to me that the problem in some cases may be poor load distribution, with too much mass at the ends, increasing inertia about the horizontal lateral axis. This is the same problem that causes sway problems, around the vertical axis.
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Originally Posted by yogiyoda
I understand that 5.0 TA is lighter but the tow vehicles used tend to be lighter too. The difference between trailer and vehicle weights might not be as extreme but you would think the same general principles would apply even if the results aren't as extreme.
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While an Escape 5.0TA is typically towed by a tug which doesn't weigh much more than the trailer, large conventional fifth-wheels routinely weigh more than twice as much as the tug.
I agree that the same principles apply... so I'm sure that a pile of cargo on a 5.0TA's rear bumper to counteract a heavily loaded front end is a bad plan.