One thing worth mentioning. Tire pressure gauges may not be accurate. Ironically the Milton gauges (a good respected name in the indusrty) are not as accurate as a cheap one with a dial I got at Wal-mart.

I took all my gauges to a large tire place and had them checked against their master gauge. I also exceed the Michelin recommendations on pressure by 5 PSI for each of my tires. I do that because I theorize it give me a little additional margin if I develop a slow leak. Both Michelin and Goodyear agree if you run a tire 20% (or more) below the recommended pressure you have effectively ruined the tire and it should be removed from service. That's a strong reason for being very careful about maintaining tire pressures.