With the current price of gas, it amazes me how many stupid people are driving around on tires that are way underinflated. I keep a cheap 12Volt air compressor and a pencil gauge in the trunk. It's especially handy if you have a flat and need to move the car to a place where you can safely install the spare.

Regards:
Oldengineer

Amen to that. Underinflated tires not only have more rolling resistance, but also get hotter, shortening the life of the tire significantly.

absolutely. If I notice a decrease in milage, I can almost guarantee my tire pressure is low. Therefore, watching my milage and knowing when it is bad also helps me keep tabs on my tires.

I find when going from winter to summer I have to actually let some air out as the temperature climbs.

Yesterday my tires were at 40psi which is 32-35psi when the temper is 32f or lower.

My car is fairly consistent on delivering 25-32 sometimes 34 on the highway. The lowest I got on the highway was with the snow tires at 34psi. Might also want to add that for fuel economy, not ride quality, put the tires up to the max on the sidewall.

Checking your tire pressure is one of the easiest things to do for your car to save fuel. It can reduce fuel consumption by over 3% (easily) For some other fuel saving tips check out http://www.all-about-car-selection.com/fuel-economy.html