Originally Posted by overlander64
...There are a number of blacktop segments that have heavy truck traffic ruts, and my Overlander and Suburban tend to be very squeamish on these segments.
I have the Reese Stratight Line Hitch, and it doesn't cope with the problem any better than your Equal-I-zer...I hope that someone with a Hensley replies, because, I too, am curious whether it might solve the problem.
i'll interpret this description as a TENDENCY
for the trailer tires/wheels to TRACK in longitudinal roadway grooves.
in automotive parlance this is tramlining
blame it on the tram ruts of daze past...
many factors can contribute to this, search and find the online references.
IF tramlining by the trailer happens and the trailer moves even a small amount LATERALLY this may be felt...
since the conventional BALL/hitches/friction control aren't capable of translation (moving laterally),
either the TV moves with the trailer laterally, OR the trailer moves alone.
IF the trailer moves alone, this movement EXERTS a steering/lateral force on the REAR of the tow vehicle...
THAT condition is a form
YAW is a better term and has been discussed here.
"seeing fishtailing" in the rear view mirror isn't the ideal way that one determines YAW or sway forces are in play.
but the NEED to provide corrective steering input IS a clue to the dynamic forces in play.
the 4 link hitches (pp/haha) prevent the trailer from exerting YAW at the tv rear axle.
because the trailer connected with a 4 bar hitch cannot normally exert YAW forces.
this is partly because the pivot point is projected FORWARD (sometimes in front of the rear axle)
and partly because the hitch head ALLOWS for the trailer nose to translate 4-6 inches laterally.
so without going into a LOT greater detail the answer is YES these fancy hitches eliminate the effect of tramlining.
it's really no different than strong side winds, bow waves or other lateral forces on the trailer...
they ALL cause yaw and prompt the driver to corrective steering with conventional hitches.
experienced/veteran folks who tow with conventional hitches accept this and have practiced SUBTLE corrective steering,
while keeping the tires properly inflated (this reduces SLOPPY lateral movement) and so on...
newer towing folks include this tramline effect
in the general description of "white knuckle driving".
pp/haha users are largely UNaware of this UNLESS the tramlining is happening to the TOW VEHICLE tires/wheels..
ya gotta experience it (the lack of yaw) with a pp/haha 2 really understand it.