Try This at HomeI noticed a clicking sound on the way back from the gym today that would seem to indicate a rock stuck in my tire. However, there hasn't been enough tread on my tires to hold a rock in at least six months. Uh oh.
Inspection in the driveway yielded a very large bolt lodged in the tire. Hey, at least it had a washer! But seriously, the slow hiss of air implied imminent failure. Yankingand failing that, unscrewingwith pliers yielded an 8mm x 30mm bolt. For comparison, this is roughly the size of one of two bolts that holds in, say, the starter motor on my truck. Or just think about your pinky, past the last joint. In other words, this sucker left a pretty big hole, big enough that the tire was totally flat in about ten seconds. If this happened to you on the highway you'd call it a blowout.
So I got out my trusty Walmart tire plug kit. A while back when I started running low on plugs I bought some of the monster truck-sized ones, and this hole seemed to justify that purchase. I plugged the tire in the normal way and inflated to about 30psi. I couldn't hear any air escaping, so I inflated the rest of the way to 50psi and shut off the compressor. (As an aside, I discovered during this process that my compressor has a leak in the regulator. It will still get up to 120 pounds, but it just runs continuously at that point without ever shutting off. So, add that to the project list).
Anyway, in the quiet, I could again hear the tire hissing, and I could see plug adhesive bubbling out. This is not normal—you're supposed to be able to drive on these things immediately at full pressure. I messed around with the plug a bit and nothing seemed to be improving the situation, so I used the cleaning tool to force the plug into the tire, leaving just a hole again, and again flattening the tire in about ten seconds.
Finally achieving true desperation, I cut another new plug in half and forced both halves into the applicator tool on top of each other. I then, with some difficulty, forced this blob of sticky goo into the hole. Repeating the inflation and testing, this double-plug solution seems to be holding.