Ryan - what you're saying makes sense. I work with bicycles everyday, and I was trying to apply your view to bicycle tires. I put 45lbs of air into a mountain bike tire (wide tread, tall sidewall), and the tire is pretty frickin hard. Then I put the same 45 lbs of air into a road bike tire (narrow tread, thin sidewall), and that tire is almost flat. Mountain bikes usually take between 35-45 lbs of pressure, whereas a road bike takes between 95-120 lbs. I know that comparing bikes to cars is like apples and oranges, but it would be interesting to know if maybe there is anything in common between the two comparisons. Comments, anyone??