I am assuming no one here has driven anything other than a Mustang, look at a Mini Cooper, those are probably 13's, that's small.
Funny you mention that. This past weekend at an AutoX event I attended, there was a '68 Mini Cooper running on 13" wheels, using ATV road race tires. $15/each! Talk about cheap! And I didn't even know ATVs road raced.
Actually...original MINIs, and even the Cooper, came with 10" wheels. That's 10" diameter!