I had about 4300 miles on my stock wheels and a set of (never flattened) Gator Hardshell tires; the tires were rotated front to back at about 1800 but the rear was getting pretty worn, was looking for cord to appear at any time. I lucked into a set of upgrade wheels (the subject of another thread recently) and decided to change to the new wheels with new Gator Hardshells installed.
Last Thursday, Day 1 with new wheels and tires: I was 18 miles into a ride in a remote local area that we call the Blackwater. I was running down a couple of hundred foot hill at around 7% at speed and hit a wood bridge at the bottom, it was rough and the bike chattered hard going across. Three minutes later, the rear was flat, I assume a pinch flat. I had a spare tube in my underseat bag but had left my levers in my shop the day before. Only 2 miles of walking got me to an area with cell coverage so I could get someone to get me. I got home, pulled the tube and found the leak on the apparent underside of the tube. There is nothing detectable on the tire interior. Put in new tube.
Friday, Day 2: A whole 14 miles into the next ride near the house, another flat, nothing apparent. Pull tire, nothing on the inside, again the puncture was on the inside of the tube. Another new tube. Only had to walk a mile this time.
Saturday (today) Day 3: By this AM I was getting paranoid, we stopped several times for various reasons and each time I would feel the tire but it was inflated hard at each check. Near the end of the ride we decided to detour some to a public boardwalk by the bay. We stopped at the beginning of the boardwalk, I checked and the tire was good; 10 minutes later and we rode down the couple of hundred foot boardwalk and my tire was flat at the end. Just DAMN!!! By this stage, no way was I going to sacrifice another tube until I got a handle on what was going on but a 3/4 mile walk got me to the cars parked near the LBS. I pulled the tire in the parking lot and noticed that the rim tape was bunched. Took the whole mess into the shop where it was determined that the puncture was, again, on the inside of the tube. The LBS owner, who was a team mechanic, pronounced that the thin, non-adhered and loose rim tape is the culprit.
I now have a new tube and new rim tape (front and rear) and certainly hope that this is over.
Early last year a rash of flat tires led me to the Gator series of tires where I had over 8500 miles on two bikes without flats, until Thursday AM.