Some people never travel far from a large city where all size tires are readily available. Others, like us, like to travel out in the less visited areas of the country where we have been 100+ miles away from the nearest gas station. For that reason, we carry an unmounted spare tire with us(the best tire left from the last tire change). CoachNet will come to us to change the tire and if we have one with us we can then drive to a tire store of our choice and buy a tire that matches what we have. This way we do not get stuck with an expensive replacement tire that may not be the same brand or diameter as our other tires.