IMHO, regardless of success, plugs are not reliable to long-term repairs. They'll get you by, but if you're going for a long-term repair, then put a patch on it from the inside.
Originally Posted By: stephen9666
As noted above, just being in the outside tread block doesn't mean it's irreparable. The real question is how far is it from the edge?
DT says it has to be 1/2" or more from the edge of the tread.
The correct repair is a combination patch/plug. This is what pretty much any reputable shop is going to install.
I agree with using a small combination plug patch that can be used 1/2 to 3/4 inches of the shoulder. They only have a 1 inch mushroom head with a 1/8 inch stem and are much more forgiving that the larger plug/patches are. I don't quite buy the first row of tread block rule, because on some tires the first tread row is a couple inches back from the shoulder.