Yes there is a formula. And NO, I didn't have it memorized, but I did know where to find it. It is very complicated and you need to know the Moment of Inertia about the hitch and about the trailer Center of Gravity. If you know these things and really want to know the formula to determine how fast you can tow your big trailer with your little vehicle before it becomes unstable, reply and I'll attempt to post the formula.
Basically, GregA hit most of the important points. One thing that I'd like to add is that if you do add a load equalizer hitch to your tow rig/trailer make sure that the hitch is adequately tied in to the chassis.
In both vertical directions.
I wanted to put one on my RV as the rear overhang severely limits the tongue weight that it is capable of handling. The rear axle acts like a fulcrum. The hitch is plenty strong in a downward direction (loaded) but I was afraid the force of the load equalizer would want to push the hitch up through the wooden subfloor of the bathroom!
Basically, GregA hit most of the important points. One thing that I'd like to add is that if you do add a load equalizer hitch to your tow rig/trailer make sure that the hitch is adequately tied in to the chassis.
In both vertical directions.
I wanted to put one on my RV as the rear overhang severely limits the tongue weight that it is capable of handling. The rear axle acts like a fulcrum. The hitch is plenty strong in a downward direction (loaded) but I was afraid the force of the load equalizer would want to push the hitch up through the wooden subfloor of the bathroom!