Hey Guys,
There have been many questions with regards to Summer/Winter wheel and tire setups, and their tire pressures lately. Hopefully this can end a lot of the repetitive threads, and shed some light on the subject.
1. What should my tire pressure be set to?
A. Your tire pressure should be set to the specifications listed on your door placard, or in your owner's manual. This is reinforced by recommendations from top tire manufacturers, such as Goodyear: http://www.goodyear.eu/home_en/tire-...-inflation.jsp
Every vehicle model is different. Weight, handling characteristics etc all come into play. Lots of research and design is taken into consideration when a manufacturer makes a recommendation.
2. What should my Winter/Summer tires be set to?
A. Same as above. Manufacturers specifications are the best bet for most drivers.
3. What is MAX Pressure, and should I inflate to that?
A. Max pressure is the maximum pressure that the tire can hold. Should the Max Pressure read 50PSI, and you decide to fill the tire to this pressure, you can run into issues once the tire warms up. During the normal operation of a tire, the air inside will heat up.
4. When should I inflate my tires?
A. Tires should be inflated when "cold". This means when the car has been driven less than a mile, or has sat for longer than one hour.
5. Can I run more/less air in my tires?
A. Yes. You can run whatever pressure you would like. Many experienced drivers prefer to inflate/deflate tires 1-2PSI from the Manufacturer recommended specs. Lower pressure generally means more traction, while higher pressure can be slightly beneficial to fuel mileage. For example, I run an extremely small sidewall (25series on a Mazda3), and inflate my tires to 34PSI to help prevent damage from potholes to my rims.
6. Can I inflate as high as possible for better mileage?
A. Some people have recommended very high (40-50PSI) pressures to obtain the best fuel mileage. While fuel mileage may go up, the increased mileage would not be very large. When inflating this high you can also loose out on traction, prematurely wear tires, and void your tire's warranty. For Example, Hankook's Warranty: http://www.hankooktire.ca/Serv/Warra...m=2&ChildNum=1
NOTE: While inflating tires drastically over/under the manufacturer's recommendations has been done many times, and will be said by some to be superior, a good general rule of thumb is: If you have to ask about tire pressure, your best to stick with tire and auto manufacturer's recommendations. They are there for a reason.
-John