Towmax blown tires

CapriRacer wrote:

gitane59 wrote:
To CapriRacer and FE:
What is not a joke is to compare sidewall strength of a ST tire and a LT tire side by side.
If after doing the comparison regardless of tread depth and the slight weight differences tread depth may produce the vast difference in sidewall strength and stiffness is not obvious to you both then we have no hope in changing your minds.......

Just so you know, I am a tire engineer and am very familiar with the strength of tire sidewalls.

But we aren't talking about sidewall failures. We are talking about failures in the belt (tread area). The strength of the sidewall has nothing to do with this type of failure. This type of failure has everything to do with the way the belt area is configured - and that is not at all related to weight.

Put a different way: The belt configuration used for LT tires can be used in ST tires. The fact that there are so many reports of failures in ST tires (in my opinion) has more to do with the level of technology applied to these tires (compared to LT tires) - and not because they are ST tires. This is likely the result of third tier tire manufacturing materials and processes (which includes 1st and 2nd tier tire manufacturers using 3rd tier materials and processes.)

The other part of the problem is that there are extremely few direct replacement sizes. This complicates matters as the way load carrying capacities are calculated is different for each type of tire. P's are different than LT's, which are different than ST's. (Please note: I disagree with FE about the load carrying capacity of LT tires when used in trailer applications.)

That's why I find this whole discussion about tire weight so funny - the key to tire durability isn't measureable by weight.

Let's take the infamous Firestone/Explorer situation some years back. The source of the problem was the material properties of the belt edge insert - AND - the thickness of the belt edge insert. The difference in weight between tires that performed adequately and tires that didn't was well within tire to tire variation. It was immeasureable. PLUS, tires produced in one plant didn't perform the same as tires produced in another plant.

I hope this explains the positions I have taken on the subject - but more importantly, the strategy used to try to fix this problem is dependent on what the true nature of the problem is. I see my role as trying to educate people as to this nature - and in particular, where they are going off on the wrong tangent.

Regarding the Firestone/Explorer situation, don't forget that Ford placarded 5k+ lb vehicles for an inflation of only 28-30 psi. Way, WAY underinflated for a vehicle that size =unloaded= let alone full of family and whatnot. No wonder they kept blowing tires and rolling. Just plain stupid on Ford's part, right along the lines of not using the proper length suspension bolts on Pintos back in the 70's.

Lyle