TD Beej wrote:Hmm... Thinking out loud here about what I am hearing is:
That as the tongue weight goes down the susceptibility of the trailer to the setup of of a standing wave goes up. Or other words if the wheels are to close to the center of mass the trailer is too easy to turn, lowering its stability and making it more sensitive to environmental inputs.
I am sure the slop at the coupling would contribute to instability but the suspension has a lot more potential for movement, energy storage and release, so good shocks should help a lot more to stabilize then a tighter connection.
Nose up/down I suspect is aerodynamics and/or weight shift. By lowering the nose more weight is placed in front of the wheels. By lowering the front you force more air to go over and less under and create opening wedge causing more of a vacuum under the trailer (side skirts anyone).
So things that can be done to increase stability are:
1. Move wheels further behind the center of mass to reduce sensitivity (decrease leverage on TV).
2. Well tuned suspension with lots of dampening (remove energy system).
3. Good aerodynamics (suck the trailer down at speed minimize lift).
4. And of course lower center of mass (shorten the "pendulum").
caseydog wrote:To simplify all this, I would just say that you need to make sure that there is positive tongue weight on you trailer hitch. It needs to be positive not only standing still, but at highway speeds.
So, you may have positive tongue weight of 50 pounds sitting still, but depending on aerodynamics, it's possible for you to go negative when you hit a high enough speed.
Getting your axle in the right place is the most important step of those you mentioned. You can fine tune the balance of a TD when traveling by simply moving gear around inside, but getting the axle placement right is the big step.
madjack wrote:Mathew, 10-12% would be considered ideal and upto 20% OK if not too much for tow vehicle...problems start pretty quick when dropping under 10%...as far as axle location goes, my rule of thumb on a standard design tear would be 36"s for an 8'er adding around 3" for every foot of increased length...39-40 for a 9'er and 42-43 for a 10'er...these numbers are not exact but will get you within loading range of "just right" to begin with......
p.s. keep in mind, it all depends on how you load...if you have a front box and where batteries/propane/dutch ovens and other heavy items are placed/located.....mj
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