I've forgotten off hand what it stands for, but I had posted something about the same thing last summer when I was working on a Schwinn Le Tour II. It does not mean "without" and it has to do with clincher tires, the bead and whether the rims are smooth on the inside or have a hook (or whatever it's called) on the wall for the wire in the tire to catch on.

Let me look for a bit & I'll post back.

EDIT: look here and see the explanation on post #48 . Apparently w/o means "wired on" as in tires with wire beads.


http://www.bikeforums.net/classic-vi...-photos-2.html