Trailer tires

Hi Gang
There is another important consideration that has not been
thoroughly dealt with in this thread and that is trailer sway with
depends critically on the tires used and their pressures. What is
trailer sway? Well you are tootling down the highway at 50mph and
everything is great and then as you go through 65mph your trailer
begins to swing from side to side much to the consternation of anyone
following you. The only way to reduce this low frequency oscillation
is to slow down fast before the situation can get away from you. So
what are the factors affecting sway? Well the weight of the trailer is
one, the weight of the vehicle hauling, where the trailer wheels are
placed (front, middle or rear) but probably the most critical factor
is the lateral flex of the sidewalls of the tires, wand of course, the
pressure of the tires. When I received my Cobra trailer from Germany
the tire pressures were low about 25psi and what I described above is
a true story. So I pumped the tires up to 40psi and no sway to 70mph
when towing with a heavy vehicle.
In researching trailer sway more fully I found the general consensus
was to use tires with very stiff side walls such as 10 ply non radial
tires (truck tires) and to keep tire pressures up close to the
manufacturers maximum pressures especially if you are going to tow
with a small vehicle. I hope this is of some help.
Dave