RAM^3 wrote:
"Nehmo" wrote in message
...
A fifth-wheel trailer is one that has a hitch that connects to the
towing vehicle at a point above the rear axle of the towing vehicle -
not at a point on the rear of the vehicle as with a pull-behind trailer.
For example, this is a 5th wheel:
http://www.theironworker.com/Fifth%2...%20Trailer.jpg
My question concerns position of the point of attachment, let's say, the
position of the king pin. For normal pulling of the trailer, where is
the best point to have the king pin? Should it be directly over the axle
of the towing vehicle or should it be ahead of the axle? If ahead, by
how much? In what ways does handling change if the position of the king
pin is changed?
Each truck's manufacturer has their own specifications as to the proper
location. Many say to position the center 2" - 4" forward of the rear axle
while others specify a position directly over the axle.
You may wish to peruse the installation instructions on the Reese website
for hitch rails similar to the ones you are interested in on the make and
model truck that you have.
http://www.reeseprod.com/support/sup...shtml#5thwheel will take
you directly to their support page.
The reason for the placement of the hitch centerpoint above or very slightly
ahead of the rear axle is to allow that portion of the weight of the trailer
that rests upon the hitch to be transferred to the rear axle without
disturbing the balance of the truck. If the point of weight transfer falls
behind the rear axle then the front (steering!) wheels are levered upwards
with a corresponding reduction in vehicle control.
Doing a wheelie down the highway while pulling a trailer will attract LOTS
of unwelcome attention! G
This page http://www.etrailer.com/faq/fifthwheelfaq.asp discusses using
a slider arrangement to move the king pin for maneuverability. It doesn'
t discuss the optimum position for towing.
The sliding hitch mount is intended to provide adequate clearance, during
tight turns, between the rear of the cab and the front of the trailer when a
short (6' or less bed) wheelbase truck is used as a tow vehicle.
Instructions that came with a hitch say to mount 0 to 6 inches ahead of
the axle, but provides no further information.
--
|||||||||||||||| Nehmo Sergheyev ||||||||||||||||
I would think that the weight of the engine would be one of the
considering factors for hitch location. Such as the Ram hitch is over
the axle, but my 94 GMC with a 350 gas engine is 3" forward. Both trucks
are almost the same length and wheel base.
The Ram clearance is 37" (pin to cab) but the 5th wheel is quite a bit
wider. I do not know what the turn angle is, but it will be far less
than 90deg.
I might consider on installing a slider so I can gain cab clearance of
a couple of inches at 90deg, that would be aproximately 11" plus the
desired clearance. My rig is 96" wide, pin location is aproximately 1"
forward of front cap. I know the Cumins engine is heavy but I dont think
I would consider runnig down the road with the pin slid back.
Any suggestions?
--
BILL P.
2004, 2500 SLT Quad Cab, Dodge Ram,
SLT, SWB, 2WD,
5.9 HO Turbo Diesel, 48RE Auto Trans,
Anti-Spin 3.73 Dif.Rhino Liner,
Husky 16K. Voyager Controller
2005, 27RL Wildcat, DT/PC Wi-Fi.
Dual EU2000i Hondas
Just Me and Dog