Back story: I recently purchased a new set of Michelin tires for my crossover SUV. They are top quality tires purchased and mounted by an authorized Michelin dealer. There is less than 6K miles on the tires.
I managed to pick up a sizable screw that punctured one of the tires and caused a slow leak, not an outright flat. I took the vehicle to the tire shop, explained the problem and they found and showed me the screw that caused the puncture.
The screw punctured the tire on the outer tread. It did not puncture the sidewall but is not far from it. The tire guy said that the tire is no longer good. If the puncture was on the inner tread it could be plugged and would be fine. He said that being on the outer tread was a different story. He said that a repair would not save the tire. Instead of having him put on the doughnut spare I had him plug the puncture and order a new tire. I’m sure I can get by until the replacement tire is available. He agreed with me on this course of action and did not charge me for the plug because he said he didn’t want to take responsibility. The tires have pressure sensors so I can continually monitor the status.
Question: Is he giving me the straight dope? Is the tire ruined or does he just want to sell me a new tire?
yes. A puncture through the belted area of the tread can generally be patched. if it’s outside of the belts (not necessarily on the sidewall) it’s not worth the risk of repairing it.
Yea, I went online to check out their warranty. They specifically state that road hazard and punctures are not covered. I can remember back in the day when road hazard got prorated against the cost of a new tire. I think I’m screwed (pun intended).
FYI, some tire stores will cover punctures as part of an extended warranty. I buy my tires from a local guy who offers this service. It’s not that much more expensive and worth the peace of mind. I’ve used the service twice.
Plugging and patching is perfectly safe, depending on where the puncture occurs. As the tech in the OP stated, if the puncture’s on the inner tread of the tire then it’s perfectly fine. The plugs are made of a similar rubber as the rest of the tire and will wear in time with the tire itself.
The problem is on the outer tread and sidewall, where the tire is generally thinner, and more prone to blowing out if there’s a hole in it. So, it’s not so much an issue of a “slow leak” as much as a spin-out and flip going 70 on the interstate.