RE: [A/S] new tires Steel vs. fabric sidewalls

["Oliver Filippi" <ofilippi@xxxxxxxxxxxx>]

Jerry,

I don't know if the old Michelin XCA truck tires with steel plys and steel
belts were any stronger than the current fabric ply/steel belt constructed
tires.

Obviously, cost is a factor in the design of any consumer product. Likewise,
in engineering, there are many ways to solve the same problem.

However, recognize that aramid fiber (Kevlar) did not exist back then, and
tire technology has advanced too.

The secret of a radial tires performance is based on two mutually coexisting
factors. One is a very flexible sidewall, the other, a  cylindrical belt
that does not stretch or squirm.  Nowadays, high performance, high speed
(sports car radials) include a nylon outer belt (or cap as it is called)
over the steel belt.  Since nylon shrinks when it gets hot, the nylon
counteracts the centrifugal force and thermal expansion of the steel belt
thus stabilizing the steel belt better than just steel alone!

So far as sidewall strength is concerned, the best indication of this is the
maximum recommended inflation pressure.  Back in the sixties, I heard many
stories of radial tires blowing sidewalls.  The major cause was probably
driving them into a sharp curb and damaging them.

Clearly, any good radial tire is going to be more vulnerable to sidewall
damage than a comparable bias ply tire.  So you pay your money and take your
choice.

Personally I'll take a quality radial any time.

Oliver Filippi