Re: [A/S] Airstream Accident in Mississippi - #3

["Maurice Riggins" <maurice.riggins@xxxxxxxxxxxxxxxx>]

The Hensley and the Pullrite are designed to eliminate the effect of
sway on the tow vehicle.  They are the only travel trailer hitches that 
can do this. They, like a fifth wheel, eliminate the mechanical advantage 
of the trailer over the tow vehicle.

Other methods used today to addres sway can at best damp sway and its
effect on the tow vehicle.  They resist an angle being put in the rig, 
be it by a swaying trailer OR by a turning tow vehicle.  There are two 
methods currently used to do this, friction or cam action.  If either of 
these methods were tight enough to eliminate sway, the tow vehicle 
wouldn't be able to turn the rig.  So they are at best a compromise.  The 
less they bind in a turn, the less sway control they provide.  Pure
and simple.

By restricting the tow vehicle's ability to turn the rig, these
methods of sway damping create "understeer," a condition where the tow 
vehicle front wheels are turned, but the tow vehicle doesn't turn, and 
instead the tow vehicle front tires scrub and the tow vehicle continues 
in a straight line.  Obviously, this is more of a problem on slicker, 
rain covered roads.

Any manufacturer of friction sway controls warns to loosen them in
the rain.  Of course, this reduces any damping of sway.  The 
Equal-I-Zer, which is nothing more than two friction sway controls 
incorporated into the spring bars, has no adjustment for the friction, 
and is disadvantaged compared to traditional friction sway controls.

Friction sway controls are even worse.  Unlike the Dual-Cam design,
which not only opposes the tow vehicle turning the rig, but tries to 
put the rig back straight, a friction sway control, including the 
Equal-I-Zer, opposes the tow vehicle straightening the rig back out as 
much as it opposes it turning it, which is also how much it opposes the 
effect of sway on the tow vehicle.  So unlike the Dual-Cam design, friction 
sway controls, including the Equal-I-Zer, can cause understeer when 
trying to straighten the rig out.

In the case of no trailer braking, or the use of a time-based ramp
brake controller, which gives no trailer braking in a panic stop, that 
we were discussing in this thread, both the friction sway control, and 
the dual-cam, may prevent the tow vehicle from getting sideways in front 
of the trailer, if they are tight enough. As mentioned, neither a Hensley 
or Pullrite, or fifth wheel for that matter, will prevent a skidding tow 
vehicle from getting sideways in front of the trailer.

However, if a friction or Dual-Cam sway control IS tight and the
trailer brakes ARE effective, this same resistive force can also 
allow a skidding trailer to turn the tow vehicle sideways with it.  
This cannot happen with a Hensley or Pullrite hitch which puts the 
point of pivot at the tow vehicle rear axle, eliminating trailer's 
mechanical leverage to turn the tow vehicle.

Besides physics, I also studied economics.  If a manufacturer is
selling all the product he can make, then it must not be overpriced.  
Pricing isn't the opinion of individuals, it's the opinion of the market.  
The market for Hensley hitches is obviously there and is buying them at 
the going price.  Sure, any Hensley owner would've love to have 
paid less money for it.  But their investment alone testifies to
where they put their priorities.

As far as overated, those who've towed for any significant time with
a Hensley or Pullrite, especially the many who towed with something 
else, rate them highly, head and shoulders above other designs.  Those 
who haven't towed with them... well, who's opinion would you want on a 
particular surgery - a doctor who's never done the operation or at best 
maybe done it a little, or a doctor who has significant experience 
with it?

Keep in mind that in the motorcycling world, or the automobile
driving world, there are many who've never been in an accident and 
needed a helmet or seat belt.  And there are some who refuse to wear 
helmets or seat belts.  That's fine with me until they preach their 
ignorant opinions to others, especially newbies. Newbies need to 
hear from those who've had experience with them in an accident.  

The same goes for sway.  There are many who will go their whole lives
never experiencing serious sway.  While many of these will decide not 
to use a Pullrite or Hensley, there are a few who seem insecure about 
their decision and feel the need to badmouth the better designs.  That's 
just human nature.  But when it's done in a forum where newbies may be, 
I find it not a lot different than the hillbillies who spew pseudo-science 
badmouthing helmets to newbies.

--
Maurice
WBCCI 5446