Unsafe at any speed....

CapriRacer wrote:
Bull Rider,

First, thanks for the photos. That really helps a guy like me sort all this stuff out. As a tire engineer, I struggle with reports of tires failing when not in service - especially when they are off the ground. It just doesn't make sense without some additional info.

I note the second photo where the finger is pointing to a cut. Yes, that is a cut. A crack would follow the ply cords and be more or less straight and radial. Plus, am I seeing cords in the cut? If so, this is confirmation that this is a cut caused by external forces.

One additional bit of info to help explain what is being seen is that rubber has a peculiar property. If pulled slowly, it will stretch quite a ways before it fails. Pulled quickly and it will fail at lower stretch levels (the engineering term is "strain" - as opposed to "stress".)

What this means is that is possible to damage a tire, but not have it fail immediately. The inflation pressure will continue to stretch the damaged area, and it will fail at a later time. That appears to be what I am looking in the photos.

So when I put this in context, my conclusion is that this particular failure is road hazard related.

Barry:

Thank you for your response. I can say with certainty that there was no cut on the tire when it was placed back on the spare tire holder last year. We were at the tire store in Quartzite for several hours and I examined all of the tires multiple times over that time period. I took several photos of the tires and the employees at the tire store also examined all of the RV tires. There was no cut.

The TOWMAX tire has been covered and the RV is stored next to our residence. We've had no vandalism or other incidents of damage to property. I can send you more photos, and I have photos of the Hercules tires that failed if you're interested.

Thanks for your input.