When I was about 25 years old, a tire was slashed on my car while it sat behind my apartment. For $350/month, the apartment building didn't have the best security (but I did have my pick of hookers, drugs, and handguns). I slipped on the spare, drove to a mechanic down the street, and asked, "So, do I need a full tire or just the inner tube?" He laughed, paused, laughed again, and then charged me double. I found out later that modern car tires stay inflated purely by the pressure of the rubber on the metal rim. Gimme a break, though. Bike tires have inner tubes...why wouldn't CAR tires??
Be honest...did YOU know?