Basically i need to know, if the type of tyre whose tread is across the full tyre width, has a patch with no tread visible outside the central 3/4 is legal, the central 3/4 has good tread but the outside edge has a bald patch with none of the original tread visible, about 6 inches long, the original tread pattern is still around the rest of the outside of the tyre, my opinion/instinct is that it is illegal