On Jan 31, 1:45*pm, scooter wrote:
On Jan 31, 12:15*am, nimbusgb wrote:

On 27 Jan, 19:20, John Galloway wrote:

At 17:48 27 January 2008, Nimbusgb wrote:

Have you noticed how the boxes on new trailers are
now square

If we're talking Cobra, isn't it just metal top - square,
grp top - curvy?

The latest square finbox I saw was on a GRP top.

I have a trailer that happily tows at 80mph and has behind a number of
tow vehicles. *I am currently towing with a short wheelbase Volvo
SUV. *This trailer is uniquely low, but seems to self damp when a semi
passes or the wind gusts and has an aerodynamic fin. *I have always
suspected it has something to do with the fin to trailer wheel moment
vs trailer wheel to hitch moment. *I have never had to play with
weights etc. *The wheel placement is different than the Cobras which
seem to be more centered.

Picture athttp://www.illunis.com/Files/trailer.jpg

Scott

My expeience is the right tow vehicle makes more of a difference than
anything I've ever been able to do with loading I've not played with
aerodynamic fixes - but my instincts are that most of these have minor
effects except in special circumstances.

In my estimation the thing that causes stability problems is the
influence the trailer exerts on the yawing motion of the tow vehicle
itself. It does this by exerting lateral force at the tow ball. That
lateral force gets translated into yawing moment based on the weight
of the tow vehicle and the distance between the tow ball and the
natural "pivot point", which is the rear wheels. I would think better
tow vehicles combine adequate weight with a short distance between the
ball and the rear wheels, plus good tire contact area to resist side
loads. I also suspect having adequate weight distribution on the front
wheels helps (that is, loading up the trunk probably doesn't help).

I've been towing for 4 years now with a VW Touareg and find it is rock
steady at any speed under any wind or passing traffic condition. The
vehicle weighs in excess of 4,000 lbs and has maybe 2.5-3 feet between
the ball and the center of the rear wheels. In a sort of ad hoc
stability test on a very straight and smooth 100 mile stretch of
Nevada highway I've towed at speeds up to 100 mph with no swaying.
Needless to say I didn't stay there long out of concern over trailer
tire ratings and a desire to stay out of jail.

9B