COLUMN: Car Talk: Modern tires are still vulnerable to blowouts

Dear Car Talk:

I have a question about blowouts. I rented a Dodge Durango for a road trip. Less than two hours of highway driving into my trip, the Dodge’s driver-side rear tire blew out.

Unfortunately, it was a total failure, causing damage to the undercarriage and body around the wheel. Luckily, I maintained control of the car and got us safely to the shoulder.

While we were waiting for a tow, I began a discussion with my friends. My thoughts are that today, tire blowouts are not random. They have to be caused by either striking something or pre-existing damage to the tire (like extreme wear or a bubble). This seemed to be proven as the tow operator pointed out significant wear on the inside of the remaining three tires.

Now, this blowout has resulted in my fighting with the rental company and insurance, as well as between me and my friends about the causes of blowouts. Perhaps tires in the early days of cars failed randomly, but with modern tires, am I right that there needs to be an external cause? — Darrell

An external or internal cause, Darrell. In general, you’re correct. When a tire blows, it blows for a reason. On rare occasions, there could be a manufacturing flaw, but the vast majority of the time, it’s due to damage.

So, here are some possibilities: The tires on your rental car could have had significant wear on them. In extreme circumstances, when combined with high heat and high speed, that can cause a blowout.

However, the more likely scenario is that you hit something in the road that instantly punctured the tire. That can happen regardless of tire condition. Or, perhaps a previous renter scraped up against curbstone while parallel parking and damaged a sidewall, creating a bubble. That’s a failure waiting to happen.

Unfortunately, unless you convince CSI (Curb and Sidewall Investigations) to take your case, it’s now impossible to know exactly what happened and whether you can pin the blame on the rental company. There are forensic tire experts. They usually get involved in lawsuits over serious accidents, where there are deaths, injuries, and potential million-dollar settlements involved. If one of them had examined your failed tire, they might have determined that you ran over a sharp object. That would be considered your fault.

On the other hand, they could have determined that the sidewall failed, in which case the rental car company might say that you damaged the sidewall because it was fine when it left their lot. If they determined that the tread separated, that would suggest that the tire was old and worn out, and then you’d have a case. However, that blown tire has already been sent to Malaysia and is on its way back in the form of 49 dog toys by now.

So, I think you need to let this one go, Darrell. One thing you can do in the future — especially now that many rental car companies are keeping cars in their fleets much longer — is to have a quick look at the tires when you do the vehicle walk-around. Don’t just look for dents and scratches on the doors. Look for bubbles on the sidewalls or tires that just look old, worn, dry or cracking.

If you see something you don’t like, note it on the rental contract, or, better yet, ask them for a different car.