glider trailer tires

jb92563 wrote:
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).

I read the articles, but I'm very skeptical. When I go to an RV show
and look at tires on the travel trailers and 5th wheels, they all have
radials on them. Ditto for when I go to a boat show and look at the
tires on the boat trailers.

The other thing I notice is a major tire company like Goodyear offers
only radial ST tires, for example, either steel/steel or steel/fabric
construction. If radial ST tires are such a poor choice, and the fact
that they are more expensive, it sure makes me wonder why they are so
popular.

Here's a quote from a 2002 Trailer life article (http://tinyurl.com/9jesg):

Trailer-tire sidewall stiffness is a compromise between P and LT
designs. The desire for stiffer sidewalls is still occasionally cited
as the reason for choosing a bias-belted trailer tire. While
passenger-car tires are nearly all radials these days, ST tires are
still available in bias-belted construction. Radial trailer tires are
superior in all respects to bias-belted tires except in sidewall
stiffness. Reduced tire heat, lower rolling resistance and softer
ride are among the benefits of radials, not to mention extended wear.

It doesn't sound like they share your concerns about radial ST tires.
Steel belted radials also have superior impact resistance compared to
tires with fabric belts.

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.

I agree with this, because I know a lot of pilots keep their tires
(radial or not) too long, because they are going tread depth instead of
age.


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.

Deflating ANY tire and letting the load sit on it for a year is very bad
practice. It's irrelevant whether steel or fabric tires are better at
it. It's dangerous - toss the tires, regardless of type, if it happens
to you.


(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!)

I tried that with a nylon comb and a steel cable like they use in tires.
Gosh, the cable straightened right out and comb didn't! This is a
worthless test.

Besides, don't you remember how badly nylon tires use to thump when
you'd first drive off? It's because nylon takes a "set" very easily, and
that is why polyester and steel are the popular materials for tires for
the last few decades. They don't take a set.

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 !

I believe the main advantage of a bias ply tire is it's lower cost.

--
Eric Greenwell - Washington State, USA
Change "netto" to "net" to email me directly

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org