One was a pinch flat and one was road debris. I do carry a spare tube and pump. I've had one flat on my hybrid and none on my road bike which I ride 80 mi a week on my commute. I keep my front tire pressure at the max and the rear at max +10 to prevent pinch flats. I was wondering if this tends to be more of a tandem specific issue due to the additional weight, and therefore, if some extra protection was warranted.