Newbee question again - flat tire on the road...

Realize now that they mount the tire on the scene. Didn't know they did that. And no, we have no way to store a 22 inch tire and with DH's bad back there's no way we could get it even out of the basement. Liked the idea of it on the roof... but then it's a real long way down to the ground and the thought of dropping it off the roof is a bit daunting.
So, we'll stick with coach net and keeping a close eye on the tires.
thanks for the information