I have a Trek Navigator 300 which is listed as a "comfort" bike (half road/half mountain) because the tires are wide smooth in the middle and knobby on the edges.
I have yet to truly take it off the road (ok, only once)....always on paved trails. So, would it be worthwhile for me to get smooth tires for it? Could I? Do they have them? I know there are size differences, but I don't know all that stuff really.