Quote:
Originally Posted by SentraSE-R
There's no way tire inflation will cause a tread bubble in a properly manufactured tire. There's simply no relationship or cause/effect rationale possible. You're crying "Wolf" where wolves don't exist.
|
I'm going to be very careful in the wording here because it is obvious that
my words are being mis-interpreted.
I am not saying that high inflation pressures are CAUSING tread bubbles,
but I am saying that it is possible that high inflation pressures may be
more prone to certain types of damage and that damage may lead to
separations and blow outs. Also be aware that I am not saying the tires
inflated to - oh, let's call it placard pressure - are immune to these
types of conditions. It's a matter of degree. People should not be
surprised to hear that tires blowout or separate at both placard pressure
as well as pressures above placard.
So here's the scenario.
When a tire is inflated, the cords within the tire are put into tension.
The higher the inflation pressure, the more that tension is. If the tire
is rolling down the road and encounters an object - and for this
illustration let's use a pyramid with a blunt (not a sharp) point - then as
the tire rolls over the pyramid, the tire envelopes the pyramid, conforming
- more or less - to the shape of the pyramid. The plies in the tire are
bent backwards and the innermost ply recieves more tension because of the
bend. That could result in breaking a cord (or cords). Obviously if the
cords starts off with higher tension (because of higher inflation
pressure), it is more likely to break.
If the number of cords broken is enough, the tire will not be able to
contain the inflation pressure and the tire will rapidly decompress
(Blowout!). However, if only a few cords are damaged, the tire would not fail immediately, but would have a weak spot, and that area would flex more, and eventually create a separation.
Obvious the speed the tire encounters the pyramid is going to have an
effect on how many cords are broken in this scenario - higher speed =
higher force. It should also be obvious that the size of the pyramid would
also have an effect.
What I am trying to point out is that separations and blowouts can occur at
both placard pressures and higher than placard pressure, but higher
inflation pressure will make the tire more prone to this.