I never really thought about how much of a difference equally inflated tires makes. My right front keeps up about 45 psi, whereas my left front will very slowly leak to thirty and stay there. I blew up the right and my tach went from just over 2000 to about 1925-1950 at 70mph. That should help out the mpg a little.

nice i knew that'* good for mileage but i could never figure out an easy way to find that out. i'll try that some time.

Yes, you will see a little better gas mileage and handling will be better, but at the expense of a MUCH harsher ride(@ 45PSI). Make sure your medical insurance is paid up becuase it'* kind of tough on the Kidneys. Also, you'll wear your tires out faster at high PSI. Personally, I wouldn't go much higher than 35 PSI.

Well, I don't know how accurate my gauge on my hose is. The right front hasn't been touched airwise since the last time it was at the dealership, so it is still set where they did. A few weeks ago I let a friend use my inflator and he noted my gauge read higher than his handheld digital thing.

By the way, the tire look really low until it hit about 40 psi.

The correct specs for tire inflation are usually on a sticker on the drivers door.

I don't have stock size wheels. Does that make a difference in PSI?

I would still use the recommended tire pressure for you car, regardless of the tire/wheel size.

That could be a problem and possibly is the reason why your tires are not really inlated properly. Those digital pressure guages are relatively inexpensive now(less than $20) and are worth it. Don't forget to check you tire pressure COLD. Usually in the morning before you drive the car.