Why do tires fail? Tires fail due to two basic causes:
- Low air pressure, and/or
- Long-term degradation of the rubber, which is usually from excess heat.
Low pressure (active leak from puncture or loose valve stem or valve core are most common reasons) can lead to a sidewall flex failure, or more commonly called a “blowout.” The sidewall cord can melt (polyester) or fatigue (steel) and end up like this tire.
Many travel trailer owners fail to realize that they will never “feel” the results of a tire losing air until it is too late and they are surprised when the sidewall lets go. The rapid air loss “bang”—even when the tire only has about 10 to 20 psi in it—is a big surprise IF they even hear it. A tire pressure monitoring system (TPMS) can provide a warning of air loss. It is good insurance and can easily pay for itself with each low-pressure warning it gives.
The long-term degradation of the rubber at the edges of the belts, as seen here, can lead to crack initiation.
These cracks can grow and unless you do a detailed inspection such as a “free spin inspection” or X-ray or a dismount and inspection of the tire interior by an expert, can lead to a belt and/or tread detachment.
Even if the tire keeps its air, you can have this type of failure. A TPMS will not provide a warning of this detachment because there has been no loss of air.
This degradation comes with age as rubber is always losing flexibility. Just think of those rubber bands you found in the back of the desk drawer. Even in cool and dark conditions they got brittle.
However, running at or near or above the load capacity of a tire will result in increased heat generation. Increased heat actually can accelerate the aging process with a doubling of the rate each increase of 18F. Running a margin of at least 15% more load capacity over the measured load is a good first step as that will lower the tire operating temperature. Running at a higher speed will also generate excess heat.
Realizing that more than half of the RVs on the road have one or more tires or axles in overload is one main contributor to the high tire failure rate. Simply thinking that a tire will fail because the tire plant building is painted blue rather than green is not logical. But I think of that faulty thought process every time I hear “China bomb.”
Buying the lowest cost “no-name” tires is, in my opinion, a major contributor to poor results. If the main objective is the lowest cost tire, why would anyone be surprised with short tire life?
Just paying more, however, is no guarantee of better quality. I believe the best tool available is comparing warranty and service support.
Things to consider when purchasing tires: Can you get a multi-year warranty on the tires? Is it possible to get road hazard coverage? Is there a nationwide network of dealers who stock the brand you are considering?
Roger Marble
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If you have tire questions, check out Roger’s Blog as well as his posts on RVtravel.com. There are hundreds of posts covering everything to do with tires.
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Thank you Roger for tirelessly educating us on tire safety! Have a great weekend and safe travels!