Ken - ok maybe we are not talking about the same thing then. When I speak about a "limited slip", I am talking about an open carrier. Like a standard 7.5" ford rear diff on most 2x rangers. When I refer to a posi - that is a rear dif where both rear wheels have power applied to them, but has clutch packs to diferentiat the turning speed while cornering. Are we just not talking then same language? I agree - a posi, needs the correct size spare, but a limited slip or open carrier rear end - this type of diff does not require the same size spare.