Update: With help of my bike guru friend, we found a staple in the tire, not real obvious and only could tell from the inside. The staple must have caused a slow leak (I thought the ride was getting softer before the flat) then at a certain deflation point, the pinch flat occurred. Disappointed a staple would penetrate this tire I purchased ($50 plus each) for it's stated puncture resistant ability but my friend believes the staple probably would have penetrated most any road tire.