Fantastic find. I wholeheartedly agree with wildman, above, about the one-piece wheels (I have two 6x6 which had them). If you don't want to convert to a 4-lug arrangement, you might find a 3-lug go-kart rim to fit, then put your own tire on. Depending on what route you choose, I've found you can't get tires much larger than 15" tall on a 6" rim.