Never have had a flat tire on either of my last two coaches, but I did have a flat tire on one of my cars. Called Coach-Net they come within half an hour and put the small spare tire on. I did not know those little tires on regular automobiles did not have air. He had a compressor filled it up, changed the tire and told me not to tow it faster then forty miles per hour, and to get a new tire for the one that had a puncture on the side wall.
Now my two cents about carrying a spare tire 22.5 on the coach is pure non-sense. They are too big and heavy, take up too much room and like a previous post stated that it ages whether you have it in a compartment or using it. So it is a waste of money and pure paranoia.