Last week we had a question from an RV owner wondering how many more miles he can expect on his tires. Here is more information explaining my answer.
The question of how many miles are left on tires is tough because some folks may only drive a few hundred miles each year, while others may drive 5,000. How many years is a bit easier.
The tire industry experts suggest 10 years is the maximum age for tires in RV use, no matter what is seen or not seen during a visual inspection. This is due to the normal “aging” of the tire rubber.
How rubber in tires ages
Rubber in tires is a mixture of synthetic and natural polymers, along with a dozen or more different chemicals. These materials are always “chemically reactive,” and the “rate” of activity or aging is temperature-dependent. The warmer it is, the faster the chemical reaction.
This aging process will lead to microscopic cracks which will NEVER repair themselves but will only get bigger and lead eventually to belt separations in steel-belted radials. And that is even if the tire is not being used. Under extreme conditions of high temperature and high inflation, tires can “fail” in just a few weeks!
Because of all these unknown variables, tire experts suggest that you inspect your tires in full sunlight or an equivalent level of light at two years and every year thereafter.
I have written about doing a “free-spin” inspection to check for any out-of-round or side-to-side bulges in the tire. These conditions can be a visual indication of internal structural failure. If anything is discovered, I recommend the tire be replaced. I cover “free spin” and tire inspection in a few of my blog posts at www.RVTireSafety.net.
No single answer
Sorry to tell you that there is no single answer based on miles or months you have placed on your tires. All I can offer is the following:
There is no 100% accurate guideline that will predict the “End of life” of a tire. It is possible to have a tire more than 10 years old still make another 100-mile trip. It is also possible to have a tire “fail” while the RV is stationary. (See pictures below.)
I have covered “tire inspection” in my posts on RVtravel.com as well as in some of my posts on my RVTireSafety blog. It is easy to find the info you need on both sites if you search for “Tire Inspection” and then review the results of that search.
The general guide of 10 years maximum life for an RV tire is based on solid information from inspecting tires at “end of life” by conducting an actual “autopsy,” where a dismounted tire is cut open with a power band-saw.
Cut tire inspections
In my decades working as a Tire Design and Forensic Engineer, I estimate that I conducted a few thousand “cut tire” inspections. These pictures show sample results. The external static inspection did not indicate the level of failure. But the “free spin” inspection quickly exposed the failure. You will need to click on the pictures to see the failure of the belts. The tires looked OK to the tire owner in his initial external “static” inspection.
The picture on the bottom shows early life conditions. This tire would probably run for a few hundred or even a thousand miles. The top picture shows a tire that could come apart in the next few days.
A “free spin” inspection would expose the large failure to even an inexperienced person.
Before you complain about my side-stepping the answer, look at these two “tire failures”:
Both of these tires had ZERO miles on them, but both had spent untold months being “baked” by the sun’s heat. Notice that both failed on the side with the most heat exposure. I have seen dozens of tires with similar conditions.
I will apologize to our faithful readers for covering the same ground so frequently. But based on the comments and questions we get every week, there are many who have apparently missed previous posts.
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.
If you still have a question for Roger after searching the above posts, send your inquiries to him using the form below.
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