what's the standard toilet paper roll girth and diameter in usa? I live in italy and it seems that tp rolls have an outer girth of 6 inches with an inner girth of 5.75 ... the difference is because of the thickness of the cardboard itself... I'm smaller than a standard tp roll with an inner girth of 5.75..but I'm almost 5.5 myself at midshaft..what do you think? have I failed the tp roll test???