Got all 4 tires replaced on my car, a few were looking pretty cracked and old. But I realized I didn't have a good mental model of how a tire works, like, how there's no inner tube or anything. Coworker explained,
http://goldwingdocs.com/forum/viewtopic.php?t=15560 had some useful diagrams (found via google image search). A tire isn't much like most other inflatable things in our life, so it's not super intuitive how the air pressure inside is pressing the rubber of the tire so firmly against the metal rim that it's airtight, even with the weight of the car and road conditions and other abuse tires have to take.
