Use lots of rubber cement on the plug, lots and lots of it.

The first plugs that I recall was about 50 years ago. I was hanging out at the gas station one day and this guy drives up. Ask the owner if he plugged flat tires, he said no, the sales guy say's can I show you something? As they walked out to his car the guy took out a ice pick and stabbed his front tire in the sidewall. The tire looked like a chia pet it had so many plugs in it. Anyway the guy took a plug out of his kit and plugged the leak, then asked , you want to buy a kit? The owner of the station said yes. I have a plug kit that I take everywhere for emergency's, but when possible I use the plug patch system where the tire has to be removed from the rim, proper clean and prep for the patch then the plug is pulled through from the inside of the tire to seat the patch correctly. Never had a tire fail from this procedure. I wouldn't recommend doing a sidewall though.

Noted! don't want no leaks

No need for lots of cement if you use the black plugs.The gray ones we got fro tech used cement.Never had one leak of either unless they werent installed right.The ones with the patch and plug are good.used them on bigger holes.Rocky

Used the black plugs (few years back), with white strips that you removed before install with tire cement in the little can. That method was okay, but sometimes you tore the plugs in half jamming them into tire tread. The most recent plugs are tan and rope like. Work well. Also never had luck with the patch/plug style that you break tire down and push through to the outside.

Thousands of brown rope like plugs used at my NapaAutoCare Center in Atlanta without one issue. Never in the sidewall. Never used on a race car tire.

Today I stopped by my tire guys' shop on the way to the store & he was not in but a co worker opinionated that the plugs are intended to get you from stranded into the tire shop and extended use can let air get inbetween the cords (I think he said cords,maybe beads) as mentioned here but of course that is his job is to steer people (business) into the shop. I will find out tomorrow where the puncture is & if it is in the trunk or still being driven on

I use plugs to get a car back on the road for a day or week or two. A nail hole in the tread should be no problem (normally) for a plug. I use plenty of cement also... needed or not. I do pull the tire when I can shortly after the flat to get a patch inside at a tire store. They cut the plug close to the casing and install the patch. Also re-balance after the repair. As mentioned, there is some risk (slight?) air may leak between the plys. Also most of my vehicles may at some time get driven at high speed and the patch inside is insurance the plug may work loose.

My lawnmower on the other hand had a hole in the sidewall I fixed with a plug. No problems in 10 years I kept that tire.

A properly installed plug will never leak air to separate the plys at the cords, and protects the cords from contamination from outside debris. While a patch seals the hole from the inside, it leaves the hole in the tread open and there is the possibility of cord damage from water or debris.

Don't over think it...just plug it if it's not near the edge (within an inch) of the tire. Tell her if she ever feels a "bump, bump, bump" coming from that tire, get it off of there. I'd bet good money it'll be fine for the remainder of it's intended service life.

After 30 + reply's,I hope you have it figured out !!

yes top notch info has been provided to my inquiry. Tomorrow I will find out where the nail entered/if still in there/if the tire has been changed out

The tire guy is not on the up and up.Ive plugged tires for at least 35 years or more.Only leaks is if not installed right or the hole is too big.Nail goes into tire plug goes into hole.plain and simple.Quality plugs last.Only way to get air into plys IMHO is if nail went in sideways and went thru plys and then into air space.but like anything it can happen like a bubble on sidewall etc.99.9999 % of the time it will not be a problem.Rocky

Drive it to the tire store and get it repaired?

We have a winner!

Today she said that her husband was checking tire pressures & he noticed the nail & it is in the tread. She also stated that he has been driving it since (~3 weeks now), not sure if daily but I would assume so (did I mention that she said he ain't mechanically inclined!). She said he ran across some one who has some equipment & he might end up taking care of it for him. she said that if he dawdles or the other person don't come thru then she will get back to me on it & if that happens I am going to get a plug kit & plug it from the outside as you have convince me that a plug will (likely) work fine with care. So we're dead in the water (for now). thanks guys!