A few of the TX sailors use very wide tires (8" or so) on 12" rims, and one told me he had replaced a worn-out tire in Houston only to have it blow before he got to Austin. Long story short, the original (and second) tire shops had both sold him golf cart tires, which are not rated for highway use. The third time was a charm, tho, and as far as I know, that set is still on his trailer.