jettafabulous
You'll get much better mileage and have a much more reliable car overall if you keep it properly maintained. This goes for all components of any car, including tyres.
To answer your question, yes, maintaining your tyres properly will improve your mileage regardless of the type of car you drive.
Cars that have a low tyre pressure typically provide a more comfortable ride, as minor bumps are absorbed better by the tyres. The disadvantage of this is worse mileage and possibly reduced tyre life amongst other things.
Some have said only to use the car manufacturers recommended pressures in your tyres. Personally I disagree and like to use a higher pressure, but each to their own. If you speak to your dealer, it is pretty much certain that he'll tell you not to exceed the manufacturers maximum specified tyre pressure. I recommend you drop into your local tyre fitter, or a couple if you're keen to get a few opinions, tell them the type of car you drive, the brand and model of tyres you have, the typical sort of driving you do, and they'll be able to recommend a suitable tyre pressure for your situation. On my car, which is a large sedan, I run 38psi on the front and 34psi on the rear tyres.
Remember to check your tyre pressures only when the car has been parked for a few hours and the tyres are cold. As you drive your tyres heat up, and the pressure in the tyres increase. Check your tyres in the morning, once a week or once a fortnight at a petrol station as close to your home as possible. Ideally you should also carry your own pressure gauge in your car to confirm the tyre pressure after you have pumped up the tyres. Petrol station gauges can be inaccurate seeing as customers throw them around a lot. A little basic pocket sized pressure gauge shouldn't set you back much over $5, and you could keep it in your basic tool box which I know you have in your car at all times in case of emergency :-)
Make sure you have valve caps on all your tyres to prevent grit getting into the valves. Also in colder months, if you don't have valve caps and you get water on the valve, then park the car overnight, the water may freeze and force the valve open, thus flattening your tyre. This of course is easily fixed by pumping the tyre up again, but it's still a pain in the arse that's easily preventable.
You should get your tyres rotated every 9000 to 12000 miles. Some say this won't gain you anything, however all car and tyre manufactures recommend it be done. If your mechanic does a good service, then he-she should remove all the wheels to properly inspect your cars brakes, so they should not charge you any extra if you ask to have your tyres rotated. ThereÕs some more info on tyre rotation here if you're unsure of what IÕm talking about:
My 2c worth :-) Hope that helps!
-- SL
"The essence of propaganda consists in winning people over to an idea so sincerely, so vitally, that in the end they succumb to it utterly and can never again escape from it"
Joseph Goebbels - Nazi Minister of Propaganda, 1933 - 1945
