Hello all,

This is a tire from the OT4R (other-than-4-runner.) Yes these are winter tires. Tread was too low to be of any use in the snow so we're running them year round until they're gone.

Someone borrowed the car, tire "went flat" when they had it, and this is how I found the flat in the trunk.

I've not seen anything like this before. What would cause this sort of tire damage?

No need to candy coat if the answer isn't pretty.

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You don't mention which side/position the damaged tire came from. From what I see, I would guess it was the front right side, and the damage came from running over something, probably metal, which cut into the tread edge and sidewall. Possibly one of those metal edged sidewalk curbs I see in some places. What did the person driving the vehicle say?

Good question... Driver's side front.

At this point I haven't really pressed the issue. Before asking about things like this, I like to arm myself with facts beforehand. Sort of like the old saying about lawyers in court not asking a question they don't already know the answer to?

It's a new teen driver (girlfriend's daughter) and her boyfriend as the passenger. I was out of town, and girlfriend told me about it when I got home.
The boyfriend's expert mechanic diagnosis passed on to me was "it just TOTALLY blew out when we were driving."

Seeing as she likes to play with her phone and he's a moron, I suspect they were misbehaving somehow or not paying attention and then said "it just happened while we were driving." It looks like impact, like a pothole or curb. If it were a pothole though, they would say "It wasn't our fault, there was a huge bump in the road and then the tire went flat." Since "Nothing happened, it just went flat" happened, that's what makes me think they were doing donuts or J-Turns in a parking lot and hit a parking barrier.

However, since the tires are from 2006, (no dry-rot, just old and ready to be replaced... just wanted to use 'em up and get my money's worth) I'm willing to accept that it might be a legit blowout.

As someone who has absolutely punished tires in my youth doing stupid shit... including smoking a set of brand new tires in 500 miles... to me it looks like its from some type of tomfoolery.

To me it looks like a tear, probably from an impact of some sort.

Generally speaking tires are pretty damn robust, it should take a lot to put one down...

It could be a pretty fat pothole, but that is a lot of damage even for that. You would know if you hit one that's for sure.

Personally not buying the "just happened" deal. My money is on the car was being used for something more adventurous at the time.

How does the rim look, any signs of damage, bend, out of round?

What car/truck was this on? Check the alignment? That can be pretty tell tail.

Since I don't see any obvious damage to the rim, I would tend to discount the pothole theory. If it was a pothole, it would have done damage to the edge of the rim. And since there doesn't appear to be damage to the inside of the tire, it would indicate the wheel hit or ran over something with a sharp vertical edge on the outside edge only. I am 99.99% sure it wasn't just a 'blowout', the edges of the tears are too regular and straight. Again, the damage to the tire is consistent with running over a sharp vertical edge which tore into the corner of the tire tread and tore the side wall as the tire went over it. Who ever was driving the vehicle drove/ran over something and doesn't want to admit it.

It is a old tire, which was just about at the end of its useful lifespan, so it doesn't have much value. But I would be pissed that the person isn't willing to own up to what really happened.

Looks like a slow speed impact failure to me. Your on the right track with a parking curb or something a parking lot. If they were at speed you would see some sidewall damage as the tire was running with the weight of the front end on it.
But I have seen (twice) old spare tire explode like that in the trunk and not even on the car. What is the age of the tire?

Age of the tire... I think it's about 2008 or so. These are winter tires that I would mount for the three snowy months, but the winters here have been so mild I haven't needed them. At the end of this winter, I just left them on to use them up and then just replace them with all-seasons. I'm a big fan of summer & winter tires, but don't expect anyone else to deal with my nonsense.

The car is my old Infiniti i30, basically a gussied up Nissan Maxima.

And yeah... I was expecting to replace them in a few months anyway, so no big deal. Not happy about being lied to, but I'd rather find out early on that they think I'm stupid and she can't be trusted with my things.

well winter tires are soft tires right?

After thinking about what @riceandpho posted... I would retract some of my above comments...

A winter compound designed to work in a specific temperature range being used in the summer could have very well been a contributing factor.

Perhaps you do want to give them the benefit if the doubt; that said, I would still do an alignment to see if there was a large impact.

From the looks of the first picture, it seems to be some type of curb, corner of sorts. You can see the impact zone and the scrapes. Around here, the cement rain gutters heave, that would match perfectly for this.

The way today's tires are manufactured, the softer traction tires are soft only in the tread area. They are generally built the same in the side wall area. What ever that person ran over, I suspect it would have torn just about any 2-ply sidewall that way.

Managing a tire and repair shop I see lots of these... that is from an impact, could have been curb, pothole,parking block,rain gutter or who knows.

I finally had the chance to look at the tire in person... here's what I see up close:

This is just too "neat" to be a blowout. I am thinking impact.

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OK, I just have to ask. In an earlier post, in response to my questions, you did say that this tire was mounted in the drivers side front position, which would be on the LEFT side of the vehicle. But, from what I see of the labeling on the side wall, that would mean you had the tire mounted on the wrong side of the vehicle. They are directional tires, and you had it turning in the wrong direction. Not that it had any bearing on why the tire failed. You can also see in the pics that there is a scrape on the side wall, just before the tear, which also indicates that whom ever was driving hit something with the tire, causing the tear.

Not trying to be too judgmental, but just making an observation.

Actually -- you are correct. I had heard it was the Driver's front, but when I actually saw the car, the spare was on the Passenger front.

It's possible I was just confused; it was a long day....