[A/S] Re: tow vehicle wants to drift at times when hitched

["overlander_64" <overlander64@xxxxxxxxxxxxxx>]

Greetings Jack!

If you haven't gone through the step-by-step setup for your hitch it 
may help -- I know that it made a tremendous difference when an 
experienced Reese technician took the time to properly setup my 
hitch.  The step-by-step directions can be found at:

http://www.reeseproducts.com/support/support/pdfs/66006IN.pdf

If the hitch head angle is a bit off, or if the hitch is too high or 
too low (even by as little as .75"), it can result in intermittent 
problems.

I would think that you are fairly close to the weight rating that 
you will need on the weight distribution bars with 750 pound bars.  
My estimate is that your hitch weight probably grosses out at about 
825 pounds.  

Having your coach weighed at a commercial scale might help to 
diagnose the possible issue.  Ideally, you would want to have both 
the tow vehicle and coach weighed separately (be sure that each is 
loaded ready for a typical tour) then as a unit with individual axle 
weight for both axles on each vehicle.  It may be a bit tedious, but 
quite enlightening; and may take a little planning as an appointment 
may be necessary for a thorough weighing as suggested.  The weights 
you will want to know include:

===Tow vehicle without trailer
=======Front Axle Weight
=======Rear Axle Weight
=======Total Gross Weight

===Trailer without tow vehicle
=======Total Gross Weight
=======Front Axle Weight
=======Rear Axle Weight
=======Hitch Weight

===Trailer-Tow Vehicle Combination
====Without weight distribution bars
=======Tow Vehicle Front Axle Weight
=======Tow Vehicle Rear Axle Weight
=====With weight distribution bars adjusted as you would for a road 
trip
=======Tow Vehicle Front Axle Weight
=======Tow Vehicle Rear Axle Weight

Basically such an exercise helps to determine that the coach is 
carrying at least 10% and more preferrable 12%-14% of gross weight 
on the tongue.  The exercise will also demonstrate the amount of 
hitch weight that is being transferred to the front axle of the tow 
vehicle.  The weighing will also help to determine that the setup is 
within the operating parameters (maximum axle weight/GVWR/GCVWR) for 
your particular combination.

With a half-ton, I suspect that you are very close to the maximums 
for weight of trailer towed as well as GCVWR.  I know that GM has 
recently significantly increased these numbers; but in 1999 when I 
ordered my Suburban, 6,500 pounds was about the maximum trailer 
weight permitted on the C/K1500 series vehicles -- my '64 Overlander 
grosses at 6,100 pounds and is why I ordered the K2500 Suburban as 
it was excessively straining the drivetrain on my K1500 Z-71 pickup 
(the motor lacked the power for the combination).  My strong 
suspcision is that much of the drift can be remedied through careful 
adjustment of the hitch.  If you happen to have one of the welded 
ball mounts and it hasn't been modified for your particular tow 
vehicle/trailer combination it could be a culprit in this situation -
- it will likely be quite difficult to find a welder who understands 
hitch geometry and can modify one of these mounts (when my local 
Reese dealer retired, I had to retire my welded mount as I couldn't 
find a welder in my area who could/would modify the welded assembly.

I would also suggest going to the website for the manufacturer of 
your friction sway control and download the adjustment 
instructions.  It is also within the realm of possibility that there 
may be a problem with the geometry of its installation with your 
particular tow vehicle/trailer combination --- particularly if the 
hitch head and friction device weren't originally mated -- I 
experienced quite unusual problems with one of my previous trailers 
when I switched tow vehicles and utilized a ball mount of a 
different manufacture that had the sway control mount in a different 
position that changed the geometry of the installation -- after the 
sway control mount was changed on the ball mount the operation 
returned to normal.

Good luck with your investigation!

Kevin D. Allen
WBCCI/VAC/Free Wheelers/Computer Club #6359
1964 Overlander International/1999 GMC K2500 Suburban (7400 
VORTEC/4.10 Differentials)
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado Convertible (8.2 
Liter V8/2.70 Final Drive)