Originally Posted by fuzz2050

I suppose some more rubber between your tube and the ground can't hurt, but I don't think it would do you much good. The extra thickness of an inner tube just isn't that much considering. I've heard tell of people using tires as tire liners (I think there is a thread in commuting).

Using a 2 tire approach, you get twice the flat protection, and half the lively, quick tire feel.