Robin,

The greatest enemy of tires is heat. Heat comes from over loading,
under inflation, high speed, and tire design. To help yourself out,
first select a radial tire, because its design inherently creates less
heat than a bias ply tire. Second, regularly check the tire pressure
before and during the trip. It also doesn't hurt to feel the tire and
the hub for heat after the first 50 miles and at each stop, just to be
proactive about any developing problems.

Sway is a function of tow vehicle, but it also has to do with the tire
design. My Cobra came with P radial tires (for cars), and it became
much more stable (with the same car and load) when I put on ST radial
tires (for trailers). As Eric pointed out, ST tires have a speed limit
of 65 mph. But manufacturers say that you can bump that to 75 mph by
(1) running 10% less than the maximum tire pressure stamped on the
side of the tire and (2) derating the maximum load on the side of the
tire by 10%.

I would guess your Komet and glider probably weigh about 1800 pounds.
A load range C tire handles 1800 pounds, so it has double the load
capacity you need - thus a 10% reduction in pressure and load should
work at 75 mph just fine. I personally wouldn't drive that fast,
although I too have a lead foot. The handling and braking of the car/
trailer combination isn't what you're used to, and you can get into
trouble very quickly because of it.

As to tire make, I found that Duro, Maxxis and Denman were recommended
(in that order) most highly by owners. Goodyear Marathons were
variable. Carlisle and Titan were not recommended. The recommendations
came from multiple internet chat groups on boats and travel trailers.
I certainly have been happy with the Duro tires that I've put on both
my Cobra trailers. By the way, I had the 165/80R13 tire size, too, and
the 175/80R13 fit under/inside my Cobra fenders just fine.

-John

On Feb 22, 5:12 pm, Robin wrote:
I want to replace the tires on my Komet trailer. The original tire
size is P165/80 R13, which is now hard to find.

The choice seems to be either a Firestone passenger car radial in the
correct size or a slightly taller Towmaster made by Greenball. The
trailer tire will have a taller but stiffer sidewall. It will come a
little closer to the fender, but my mechanic says less than half an
inch closer. The size is 175/80 R13.

I plan to tow about 75 mph most of the time. I really want to avoid
sway.

Any experience with these tires out there?

Thanks,
Robin RF