No problem, I had two spares. I pulled the bad tire, grabbed the spare off the roof and went to put it on. Uh.... problem. The spare wheel would not fit over the drum on the trailer. The bolt pattern was correct. The tire would work but I didn't try it on as my smart wife had suggested. We were now on the side of the highway with a bald tire that had no tread and two worthless spares (they were identical). The bad tire was still holding air so we limped to the next town and were able to buy two used tires and continue. I bought two because the other tire, which was as old as the "bad" one was about to throw its tread also.
About twenty miles from our destination there was an enormous BANG and the whole truck shook violently. One of the "new" used tires exploded.
We were able to see my nephew before he was deployed to Korea and will work on finishing
the trailer while here.
Now we are at my parents house trying to get rid of a Van some truck parts and a few other anchors that we have so we can get to Texas and go to work and continue our travels.