I've never had anyone answer this to my satisfaction yet, and I'm hoping the brain trust here has something to offer. Why is it that tubed tires leak so much. I add air to our bicycle tires every couple of weeks. I add air to the plane tires every couple of months. I add air to my auto tires - ummm - never. I would think tubed tires would leak EVEN LESS than tubeless but the opposite seems to be true. The tube is, in my mind a closed-system with the only in/out to be the Schrader Valve. Why oh why? Does the tube itself leak air through the rubber by its nature?