how tired is this tire?
July 3, 2018 5:25 PM   Subscribe

I backed out and pinched my tire against a curb. The curb bit back. Is it totally borked? Pic
posted by Dashy to Sports, Hobbies, & Recreation (14 answers total) 2 users marked this as a favorite
I had a similar divot, and when I took it to the shop they said as long as the belts/cords aren’t showing it’s fine. YMMV (har...har...)
posted by doctord at 5:41 PM on July 3, 2018 [1 favorite]

Yeah, can you see the belts/cords under that divot? If those are exposed, your tire's life is over. If not, keep an eye on it and ask about it at your next regular service.
posted by Anticipation Of A New Lover's Arrival, The at 6:05 PM on July 3, 2018

I see cords & a compromiseD sidewall. I’d say it’s dead.
posted by tilde at 6:08 PM on July 3, 2018

Response by poster: I can't see cords. Might just be the pictures- in reality I just see rubber in the divot.
posted by Dashy at 6:24 PM on July 3, 2018

It looks almost like there's a flap of loose rubber concealing more damage. I'm not liking that. Hard to say from a single angle picture and not being able to poke around at it. I'd get some professional eyes on it sooner rather than later just to be safe.
posted by Larry David Syndrome at 6:32 PM on July 3, 2018 [2 favorites]

I would replace that tire. It will probably be OK, but I wouldn't risk it.

I say this as an old Accident Investigator. I have some sorts of phobias about easily repairable things that cause death a lot. This is one.

You noticed a fucked up tire. You saw it. You ignored it. When you blow out at 70 and swerve all over and crash because of it, it's on you. The other people that are around you in traffic didn't know. What if they swerve to avoid you and have a big crash?

That's all on you. Sidewall failures are the worst. There's a reason it makes you buy a whole new tire.
posted by sanka at 7:29 PM on July 3, 2018 [10 favorites]

Yeah, in my recent experience that exact interaction with a curb = borked tire. I would get it checked out and, if you can afford to, replaced rather than patched.
posted by Hermione Granger at 8:10 PM on July 3, 2018

Tires are cheap. sliding sideways own the road isn't.
posted by Afghan Stan at 9:26 PM on July 3, 2018

A tire with sidewall damage can’t be patched.

In my younger less affluent days I would have gone and gotten used tire for 25 bucks rather than keep driving on a tire with sidewall damage. That’s because my family raised me up in the car biz and taught me a lot about car maintenance and sidewall damage was pretty much always “yeah you could drive on it or you could do the most correct thing and replace it”.

Basically look at your tires like this: could this tire be resold as a used tire? If not, replace it. That tire can not be resold. Under my logic I would replace it.
posted by nikaspark at 9:32 PM on July 3, 2018 [3 favorites]

How tired? So tired it needs to be out of its misery.

I have been known to put a substandard tyre in the spare, and put the spare on the wheel. However that was more like marginal tread wear than potentially serious damage, even potentially fatality-causing damage. Just get a new one in this case, and sleep well, drive with confidence.
posted by GeeEmm at 2:27 AM on July 4, 2018

Another vote for sidewall damage means that the tire gets replaced. I thought that was common knowledge, and I hope that people saying otherwise will reconsider.
posted by kellyblah at 5:57 AM on July 4, 2018 [1 favorite]

Replace the tyre. The pinch looks like it was over a decent amount of the sidewall and you could have pinched it in a way that is not visibly obvious and weakened the belts internally.

A tyre failure is no joke - often a guaranteed accident, because they usually fail at high load (ie high speed). Replace the tyre, it's just not worth the risk.
posted by Brockles at 6:06 AM on July 4, 2018

Best answer: Most tires have steel cords. Think of tiny cables with multiple strands lying side by side and encased in rubber. The tread surface of the tire has multiple layers of these steel wire cords forming belts crisscrossing the tread area. So multiple belts = very strong to guard against punctures and impact damage.

The sidewall is much weaker. The sidewall has a single layer of vertical steel cords sandwiched in the middle of a layer of rubber which often is only 1/4" to 3/8" thick. When the sidewall has an impact the individual cords can be bent or cracked in such a way that they no longer will hold the rubber together.

In your case the outside layer of rubber has a divot taken out. Because the steel cords are not visible does not mean they are undamaged. Also if there is even a tiny crack which exposes the cords they can readily absorb water and begin to rust which would also lead to failure. Once any of the cords are damaged you are basically left with a balloon - just a very thin piece of rubber trying to hold back air pressure.

One of the reasons running a tire below its recommended pressure is so damaging is that the sidewall is no longer rounded. At every revolution the steel cords are flexing back and forth at a sharp angle. If you've ever kinked and bent a steel wire back and forth you know it will very quickly break. That is exactly what happens in an under inflated tire. And the damage often remains hidden since the rubber can flex and then return to close to its original condition. But the wire inside can break and leave just a thin strip of rubber holding in the air pressure. This will definitely lead to a catastrophic failure, loss of control, etc.

Next time you are near a dismounted tire or display, place one hand inside and one outside the tire to feel how thin the sidewall is vs. how thick the belt package/tread is. You will look at your tires in a new way.

If I had a tire like this on my vehicle I would drive (slowly - not highway speeds) to a nearby shop to have it replaced.
posted by tronec at 7:54 AM on July 4, 2018 [6 favorites]

Yeah, I would not drive on this. I may be overly cautious because I ride motorcycles where a tire blowout is much more likely to be life-threatening, but even in a four wheel vehicle it will ruin your day, and could potentially kill you.

Tires are not so expensive that it warrants risking it.
posted by 256 at 11:26 AM on July 4, 2018

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