Re: [A/S] Sway - #3

["trucks98225" <alweaw@xxxxxxxxxxx>]

There is no question that proper weight distribution has a major 
effect on stability.  Nevertheless, hitch designs are a factor as 
well.  A passenger vehicle (car, pickup, etc.) pulling a trailer has 
the pivot point well behind the rear axle.  This is a stinger-steered 
combination.  Lateral inputs at the rear of the trailer require a 
compensating action on the part of the tow vehicle.  A fifth wheel 
has the pivot point over the rear axle and cannot impart a lateral 
input to the towing vehicle.  Hitches such as the Pullrite and 
Hensley attempt to mimic the behavior of a fifth wheel coupling.  The 
Pullrite actually moves the pivot point forward to the rear axle.  
The Hensley uses a 4-bar linkage in the design that achieves a 
similar effect.  A kinematic model of either hitch will show how each 
behaves.

Personally, I made a decision to use a Hensley hitch to improve the 
overall vehicle stability and margin of safety.  As an engineer, 
there is no question in my mind about the kinematics of a tow 
vehicle/trailer combination.  Marching to a "different drum" doesn't 
change the laws of physics.