Flat as a flitter

I had an unusual flat yesterday. I was driving home and was in Denton, TX. My wife and I commented on how smooth the ride was as we were coming into town. I pulled up to a red light at IH35 and 380 and had to wait a minute or so for the green. As soon as I took off, I immediately knew I had a flat on the left front of my DP motorhome. I hobbled across the underpass and found a 7/11 type store at the corner on the other side. I pulled in behind it and after getting permission, changed it on the spot. I noticed two large gashes in the sidewall but those may have been from driving from the light to the 7/11. This was on a new tire (about 700 miles on it). Changing it took me the better part of an hour. Cranking down the spare from its underneath storage is a PITA.