Monday, December 5, 2022


RV Tire Safety: Tire autopsies of run low flex failure and impact break


I thought it might help to show a couple of examples of what was observed while doing a “tire autopsy.”

First tire autopsy

A tire would be received with a complaint letter. The letter might say something like, “I was driving down Route 66 at 55 mph when suddenly I had a blowout. I wasn’t speeding and had checked the inflation just that morning. What is wrong with the tires? There must have been a defect.”

Run low flex failure

The tire looked like this:

Another view:

On close inspection, I found what looked like a hole in the upper sidewall where the rubber had been worn away.

Using a bent paper clip,

I was able to confirm the hole. Looking inside, we can see where the puncturing item went.

Note: A bent paper clip will fold at the bend if you try and push it through a tire sidewall. But if there is a hole, the paper clip can follow the hole. For this case, I provided the above information and pictures.

Second tire autopsy: Impact break

Another complaint involved a bulge in the tire sidewall. The location was marked by the tire dealer.

On the inside, we see a lump.

We can also see a dark curved line where the tire had extra bending.

By cutting away the rubber from the inside of the tire, down to the body cord, we can now see the broken cords from the impact.

I trust that after seeing these examples you have learned that sometimes additional examination is required to find and confirm the actual tire failure cause.

After doing hundreds of similar examinations, it allows the experienced examiner to quickly identify the reason for a tire failure was not some design or manufacturing “defect,” but the result of external causes.

More like this in future posts.

Have a tire question? Ask Roger on his new RV Tires Forum here. It’s hosted by and moderated by Roger. He’ll be happy to help you.

Read more from Roger Marble on his blog at or on


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1 month ago

Hi Roger, as usual you’ve provided some excellent information on tires! I thought the bent paper clip was an excellent tool & its really cheep! I also have followed Jim J. advice on getting tire hazard warranty, but be sure to read exactly what you are buying!

Jim Johnson
1 month ago

The other lesson from your knowledge? I always pay for a tire hazard warranty. I do my best to treat my tires well, but things happen… I managed to pick up a muffler clamp U-bolt 18 months ago. Two big holes. Fortunately was able to park in a safe place before the tire fully deflated and easily get my bottle jack under the camper frame.

1 month ago

I’ve really learned a lot with your column on tires. No matter how simple it looks there’s more than meets the eye.

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