Repairing a tire

My tire got cut by running over a piece of metal. What is making it difficult is that it is not a hole that can be plugged but a 1/2" to 3/4" straight cut through the tread. My regular tire store won’t repair it because it is not a 1/4" or less hole. It seemed to me that buying a plug kit and laying it sideways and pressing it into the cut from the inside then covering it with a patch would fix it. Then I would get the shop doing the patch to remount and balance it.

Any thoughts on that procedure? Any other ideas?

I wouldn’t attempt to patch a cut like that. If you examine the cut then I’m sure you’ll see several steel wires that have been cut. Those wires are what gives the tire the strength it needs to do its job. The kind of repair you’re talking about is a blowout waiting to happen.

It stinks but buying a new tire is your only realistic option. You might want to buy a tire with a road hazard guarantee.

This can never be a dependable safe tire. How much is your life worth? If not yours, mine is worth you not coming at me with this tire. Don’t be like that guy that had TB and was flying all over the world possibly spreading it. I’m hopeful that once you understand the facts here you will go buy a safe tire and know that you were not throwing away something of any value.

Not discounting the above comments, “back in the day” one would patch (vs plug) the tire and then use an inner tube.

Do they even make inner tubes anymore?

Yea, that’s road hazard, not a puncture. The tire is toast. It’s dangerous to ride on given the handling characteristics and speed of modern cars. The tire store is right in refusing to repair it. They don’t want the liability nor should they.

Buy a new tire. No patch is going to fix the pretty seriously advanced construction that goes into tires nowadays.

Fill in with straw.

The point where the steel wires have been cut will flex with each revolution, creating heat and physical damage.

That spot will weaken quickly and fail, perhaps catastrophically. If you hit me or mine because of it, I would be less than gracious about it. If you roll and kill your kids or wife, you’ll be unhappy.

Buy a new tire. Not a used one.

ducati. mechanic for 30+ years.

The reason they use tubeless tires now, especially with radials, is that the flexing between a tube and tire creates more friction and heat increasing the chance of a blowout. Radials flex a lot more that the old-fashioned tube cloth-ply tires were supposed to. (Radials often look slightly undeinflated).

Plus, if it’s a slice, what stops it from slowly pulling apart like any other long hole in a flexing medium. It’s not like you can drill a hole at each end of the cut to help stop the crack from enlarging, like they do with metal cracks. Every revolution, the flexing of the tire is encouraging it to pull apart a bit more, causing the crack to lengthen.

this would be a bad idea for a couple reasons-

  1. a puncture or cut like this tends to push strands from the steel belts up into the tire. These would likely puncture an inner tube in short order.

  2. if this is actually a slice and not just a small hole, then the belts are damaged and the tire is structurally unsound and no longer safe to drive at speed even if you plug the leak.

The tire is destroyed. Any attempt to salvage it other than a dire survival situation like the Straw(input any organic filler) packed tire to slowly transport one out of a predicament would be negligence.
I do like the straw fix. One would not need to remove tire/wheel from vehicle to pac it, and I would use triangular flaps instead of the big rectangular flaps.
The tire not breaking loose from the rim would be a large factor in this working IMHO.

There are times when you have to bite the bullet and replace a tire (has happened to me more than once), and this is one of those occasions.

What gets cut is the nylon cords. These run from bead to bead, and are what actually contain the pressure. The steel belts end at the edge of the tread. If one or two get cut by a nail, you are probably still OK. If 10 in a row get cut, like a 1/2 inch gash, then you have a problem. The cut cords allow the the tire to spread around the plug and it will not stay in. If you put a tube in there, the hole will expand with pressure and the tube will pooch through and blow.

If this happens on a bicycle, you can usually get home by patching the tube and laying a “boot” between the tire and the tube. A boot is a piece of an old tire, or a piece of tyvek shipping envelope, or even a dollar bill in a pinch for fat low pressure tires…or it could even be a genuine Park tire boot you payed good money for in a bike shop. Booting is strictly a “limp home” fix, and not for high speed tires. I might try it on a motorcycle if I was way back in the woods with no other good options, but certainly would not ride/drive a booted tire at highway speeds.

How many miles do you have on the tire? Many tire manufacturers warrant their tires up to a specific number of miles. If you still have the original receipt when you purchased the tires, it may still be under warranty.

Thanks for the answers. I’m glad that I was able to get an answer for the why rather than the “I can’t fix it, you need a new tire.” that sounds to the customer like “I’m screwing you into buying a brand new tire rather than fixing the one you got.”

If you’re on a farm, you take that tire and use it on a hayrack. They don’t go very fast, or very far, so it should work for a while, and won’t cause much problem when it eventually fails.

But don’t use it on your car, as people have explained.

It’s important to remember that the nylon cords are what actually transmits the force from the rim to the ground. Once one of these is damaged, things will only get worse.

Although the question seems to have been asked and answered, I’ll point out that rocket motor manufactures have made essentially the same argument, with basically the same response, e.g. it isn’t worth the risk of your program to lose pressure integrity from essential fiber damage. Those who have ignored this advice have lost billion-dollar programs, which is clearly not a smart move.