Unsafe at any speed....

Turtle n Peeps wrote:
Thank you for your insight and no criticism taken about the pictures. Barely got those off before the camera went dead.

Anyway, bottom line. IYHO what causes these types of failures?

It is construction, contamination or materials?

To me it looks like they are not using enough "glue" to stick things together. IOW's all of the plys are separating from each other and the casing. The plys and casing still look good to me but they are separating. Michelin had huge problems with this X Radial make of tire doing this. This is why to this day I won't put a Michelin tire even on my wheel barrel.

I was told in the cap world, this is caused by contamination. What about new tire world?

IMHO, this is all about context. Different kinds of tires suffer from different kinds of issues.

In the case of passenger car tires, it's been demonstrated that inflation pressure is a big contributor. Since inflation pressure is directly related to load carrying capacity, this could be stated as a load issue.

But when it came down to fixing this, all the tire manufacturers changed constructions.

In the case of large P metric's and LT metric on SUV's and pickup trucks, the inflation pressure situation is even worse - and again related to load carrying capacity.

P metric tires on SUV's were particularly of interest a few years ago - the Ford / Firestone situation. This was, IMHO, primarily a materials properties / design issue.

However, tire manufacturers improved the performance by changing constructions.

LT metric tires had issues too - and those were fixed by changing constructions.

We also know that loads on ST tires are suspect. But here we have some common denominators that are interesting - and that is that many of these tires are made in China.

Here the problem remains - and based on the fact that construction changes eventually fixed these issues in other type of tires, I would presume that construction changes would fix those as well. The fact that many report success with LT metric tires seems to point to using the same construction as an LT tire.

So what do I mean by "construction changes"? These are details about the thickness and the material properties of the belt edge insert (between the 2 belts). Cap plies is also something that improves the situation. There is also some belt edge treatments that have been used successfully.

And then we have the age issue. Every time an analysis is done about where these failed tires are coming from, the same 5 states always rise to the top - and more or less in order: AZ, CA, TX, NV, and FL. FL may seem the odd man out, but if you compare the yearly cycle of temperature for - say - Orlando and compare that to - say - Phoenix, you'll notice that the temperature in Orlando is warm all year round, where the temperature in Phoenix is only hot in the summer. I think this has to do with heat history. While FL doesn't get as hot, it gets heat year round.

Contamination? Haven't seen it - and that fact the construction changes also seem to be the answer, seems to confirm this is not the issue.

Or perhaps you could say, that whatever the true issue is, making construction changes overwhelms the problem enough to render it moot.