Check out these articles:

http://www.advanceautoparts.com/engl...0040501tt.html

http://www.championtrailers.com/tire_art.html

Basically you need ST tires of the Bias variety for a glider trailer:

The Bias and Bias Belted (nylon) tires give you better sway and load
control, where radial
gives you longer treadlife and more flexible sidewalls(less sway
resistance).

The radials with weaker sidewalls sway more, and eventually all that
sidewall flexing could cause steel belt fractures, once fractures the
belts migrate out through the sidewall weakening it further and
contributing to a sidewall blowout.

Generally people keep radials far to long since they last longer in
terms of tread wear, but to risk your glider and trailer, and perhaps
much more is not wise.

As far as the material memory.....try this test.....deflate your
radials and let them sit for a year.......now inflate them and take the
trailer for a spin......that horible bouncing drive down the road is
due to bent steel in your steel belted tires.....sure it will smooth
out after a while, but its because the belts are broken now and after a
while you will notice steel wire exiting your tire sidewall.

Do the same with nylon tires and you wont even notice anything and the
integrity of the tire is maintained through out the exercise because
nothing actually broke internally.

(More simply....bend some nylon (comb?) a bit and release...how long
before it straightens out on its own?....now try with a peice of
steel...how long for the steel to straighten on its own?......theres
the POINT!)

Im frankly amazed that this is not common knowledge about the Bias
tires being best for glider trailers because of the way we treat our
trailers, leaving them alone, deflated and neglected frequently !

Ray