Tuesday, March 21, 2023


‘Defective’ tires: Just what is the ‘defect’?

I have heard people claim they had a “defective” tire when they post about a tire failure. I have even addressed claims from lawyers and supposed “experts” that a group or even thousands of tires had “a defect” that caused tires to fail. However, for some reason, they can almost never point to or identify the specific component or material that contained said “defect”.

I spent the majority of my 40+ years as a tire design engineer looking at and investigating tire failures. I can say that I have identified a few tires that contained a “defect.” But before I continue we need to be sure we have a common understanding of the word “defect” and what we mean when we use it.

Definition of “defect”

Merriam-Webster says the meaning of “defect” is “an imperfection or abnormality that impairs quality, function, or utility: shortcoming, flaw.” I note that they are not saying that an item has a defect if it has failed to perform. They are talking about a specific “imperfection or abnormality” in an item.

I sometimes offer the following in an effort to clarify the concept. If we discover a dead body, should we always assume that the person was murdered? Of course not. But jumping to a conclusion about the most extreme cause seems to be what some want to do while ignoring the need for a thoughtful and reasoned collection of facts and evidence.

Tires can fail for dozens, if not hundreds, of different contributing factors, but most do not involve design or manufacturing mistakes. When I read a post on an RV forum or receive an email about a “failed” tire, I do not start with the assumption that there was a manufacturing or design mistake. I do start with a close examination of the tire, wheel, and valve, as many times the evidence is in front of our faces. The question is, are we willing to take the time and make the effort to look for the evidence that is almost always there?

Why people might use the word “defect”

I believe that many times some people use the word “defect” as they do not have the knowledge of how to do even a basic inspection. That is understandable. But if we want to avoid a repeat, wouldn’t it be best to learn the real reason for the failure and take steps to try and prevent a reoccurrence? What bothers me, though, is when I hear lawyers or reporters use the word possibly to grab the attention of those reading an article. I believe that a headline saying “Another RV tire failed, facts to follow” would not gain much readership.

In my posts here on RVTravel.com and in my RV Tire Safety blog,  I have provided numerous examples of failed tires that were initially claimed to be “defective” such as the following examples.

A tire that was run with low inflation.

One that has an external cut.

Or this tire with a plug in the sidewall.

Or this tire failure below that was due to leaking air. This failure even ended up on YouTube, but the video did not mention the evidence of the tire having been run with very low air pressure.

Currently, there are news articles mentioning failures that occurred many years ago on some RV tires that might have been improperly installed on some heavy RVs. While I have no details, I do recall reading the word “defective” in the article, but no mention of what the “defect” might have been.

Did a “defect” really cause the tire failure?

I would suggest that when you read a “news” article about tire failures and find the word “defective,” you stop and see if the author mentions what the imperfection or abnormality was in the tire that caused the failure.

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

Read more from Roger Marble on his blog at RVtiresafety.net or on RVtravel.com.



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1 month ago

Thank You Roger. Very informative article. I have over the course of 35 years of towing experience with many hundred thousand miles have had several blown tires. I do not think any of these were manufacture defects. Mine were #1. Overloading and over speed. #2. Under inflation. #3. Curb checking (also includes campground rock barriers). #4 Belt slipping caused by tight backing into campgrounds or work areas. I am not afraid to admit my own failures. It is not the tire in most cases.

1 month ago

I believe we’ve been spoiled by safety redundancies built into car tires. No car or truck manufacturer would install tires that are barely rated for the weight they’ll carry, with a 65 MPH speed rating. Yet RV manufacturers routinely install the cheapest tires they can get by with; then the consumer replaces those in kind when they fail. When I had my first blowout, I got educated, upgraded from 10 to 14 ply tires, added tire pressure monitors, and enjoyed 35,000 trouble-free miles.

Wayne C
1 month ago

Remember, Lawyers and reporters are not under oath to tell the truth, the whole truth and nothing but the truth. They can say anything they want that will sway those listening to their objective.

Bob p
1 month ago

Most of the time the defect is the owners failure to check tire inflation pressure prior to departure. Just because a tire “looks ok” doesn’t mean it’s properly inflated, then drive at 75mph for 3 hours at 15 lbs low on pressure. It’s going to blow!

Roger Marble
1 month ago
Reply to  Bob p


1 month ago

Take care of your tires and they will take care of you.

1 month ago
Reply to  tom

Agree completely. Check them often, not just each oil change. Now, if we could just get the manufacturers to add an effective, simple valve stem arrangement for all dually wheels. The mixed reviews about add on extensions do not inspire confidence.

Roger Christianson
1 month ago
Reply to  Dan

I agree with you on this. The valve extensions on our class C dually were always the main cause of low pressure. I have removed them.

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