What wrecked this tire?

Maintenance/Repairs
21

That tire was not driven flat unless it is a run flat tire, but it did hit a road obstacle or curb. My first though was that someone drove over one of those one way things that shred your tires when you go over them the wrong way, but then how would it get home without scuffing the sidewalls.

Modern tire do normally “slow out” rather that “blow out” but a rip that size would deflate almost immediately.

Did your neighbor actually see the person when it was returned? Could they have been at home when it was returned but not actually see it in the driveway at the time of return? If the borrower had hit something, they could have put on the spare, drove the car back to the owner when they weren’t home, then changed the tire back. That is the only explanation I can come up with based on the pictures.

Maybe check with other neighbors to see if anyone saw the vehicle being returned or the tire being swapped in the driveway.

Edit: looks to me like the tire was made in April 2014.

22

I’m in agreement

23

Thanks for the photos.

Yes, Photo #4 does indeed look like the date code portion of the DOT code. The first 3 digits (863) look like the Type Code and the last 4 digits (1414) look like the date: 14th week of 2014. This photo is obviously on the inboard side of the wheel.

Notice that those numbers are not imprinted in the mold but on a plate. That would not be unusual for the date code, but it is a bit unusual for the type code.

Also notice the there is an “N” the immediately proceeds that plate and it is imprinted in the mold.

Then go to Photo #6. It shows the letters “DOT”, followed by “CC9N”, Not only does CC identify this tire has having been made by Yokohama in Salem, Virginia, but the “9N” is very likely the size code, but they are NOT using the RMA size coding formula (which they don’t have to!) - AND the font is the same as the “N” in photo #4, thereby confirming that that plate is indeed the type code/ date code! This photo is of the outboard side! That makes sense!

The little “13601” is very likely a mold number or a drawing number.

Just an FYI: The DOT code has to be about 10 mm high, and those numbers clearly aren’t.

Now onto diagnosing the failure - again, thanks for the additional photos!

Any tire that was run flat is going to show abrasion in the mid sidewall area. In this case, though the “YOKOHAMA” in Photo #5. So the tire was not driven on flat, but went flat in the driveway.

A tidbit of interesting information: Rubber has an unusual property in that when stretched quickly it will fail at a lower value than if it is stretched slowly - and this tire appears to have failed like some other tires I have seen that failed in storage. long after they were removed.

Best guess is that the tire was damaged by an impact, but it was not rendered unusable (as in it still held air) until it lost air in the driveway (and not moving). It’s quite possible the air loss was slow enough not to cause a “Bang!”

Side note: Now you have seen what I did for a living. I provided this kind of analysis to one the major tire manufacturers for many years - and I was not alone in having that capability. It is indeed amazing what you can pick up with just a photo. Imagine having not only the tire in front of you, but X-ray and holographic equipment. It really helps when advising tire designers as to where the problems are!

5 Likes
24

What do I know, but doesn’t that look like a little dry rot in the last couple of pics? Kinda unusual for a tire only 6 years old? Maybe not if out in the hot sun all the time.

1 Like
25

Thanks for the additional info. I gave my neighbor the link for this thread; maybe she will look at it.

The neighbor hardly ever gets out these days. I get a good view of the passenger side of the car when I look toward her house. (Sometimes I go into the carport and see the driver’s side.) The most puzzling thing to me was that the car had been sitting for a week or more, looking normal. Then, I noticed that the tire had gone flat. I figured it was a typical slow leak, until I saw the damage to the tire.

MAYBE the car had been used for part of a day when I was not watching, but for sure, it did not get driven home with the tire damaged like that. Some you experts have given credible scenarios, and that’s good enough for me.

26

Looks like a typical 6yr old tire to me

Not to brag, but my sample size is huge, because I turn wrenches for a living

27

No offense to an ex-pert but I think you should look closer. Next to the last picture, upper right. Doesn’t look very healthy.

28

What I see is a lot of abrasion. Other photos of the same tire don’t look nearly as bad. Weather cracking would be in those photos, too!

1 Like
29

I see that, I had not given it significance but now your explanation makes more sense than mine. Possibly the borrower hit something like a concrete block in the road and the tire did not quite come apart, but did develop a soft spot that would have made a noticeably harsh ride returning it. That would have abraded the area around the impact but not the rest of the tire as much. It later gave up the ghost in the driveway.

Edit: the borrower may have thought the harsh ride was caused by throwing a weight off the wheel after the impact.