On Oct 16, 3:35 am, "HL Falbaum" wrote:
OK--I'll supply one.

1999 Chev Tahoe
1999 ASW27 + Cobra
Tongue weight about 9%
all tires new

Begins sway at 68mph--diverging oscillation above 70 mph.
Tried spoilers on vertical fin--no help
Used nails as wedges to stabilize hitch in the receiver--no help.

Attached same setup to a Ford Expedition--stable at up to 110 mph!

Bought 2003 Chev Avalanche
Stable at any speed traffic allowed!

The difference---The 1999 Tahoe had a soft suspension and "vague" steering.
The Avalance and the Expedition are much more stiffly suspended and the
steering more precise. All three vehicles are massive compared to the
Cobra+'27

The answer--IMO the "natural frequency" of the suspension no longer
resonated with the trailer suspension "natural frequency" at highway speed.

Of course different tow vehicles will tow differently, particularly
with SUVs, many of which use suspension which can only be described
politely as being "agricultural". My point (which I did not explain
clearly) was that I doubt that if you had, for example, tried a
negative noseweight or stuck a bunch of lead acid batteries in the end
of the trailer your Tahoe would have towed at high-speed with
stability.


Dan