If you live in the northern tier of states in the USA, you know that cold weather has set in. In preparing your vehicle for winter, one item that SHOULD be at the top of the list is checking your tire`s air pressure. I know that many newer vehicles now come with tire pressure monitors, but they may not come on until you have a serious tire pressure problem or low tire pressure (usually below 22 PSI). I am reminding Autopians to do this because tires generally loose about 1 pound-per-square inch (PSI) of pressure for every 10°F drop in in ambient temperature. So the last time you checked your tires at this early fall at 70°F may be 5 pounds lower when it is now 20°F and that can impact in how your vehicle handles, its gas mileage, and how tires wear. Also, if you have aluminum rims (as many vehicles do these days) you will loose air through that porous metal more quickly than with steel rims.
If it has been a while, you should also check the spare tire in the trunk or under the vehicle frame, if it is so equipped. MOST collapsible spare tires require an inflation of 60 PSI to be considered safe for use, and while it is a pain to remove to check and inflate to the proper PSI, its also much bigger "inconvenience" should you need to use it in an emergency in the middle of no-where.
Most vehicles have a tire inflation information placard either in the glove box OR on the driver`s side door sill frame for the OEM tires. If you have a different set of rims and tires than what came with the vehicle, you may need to consult with the tire manufacturer for that vehicle.
Personally, I inflate to about 1 PSI OVER the recommended amount on the placard. Those recommended tire pressures are usually for the best comfort in ride and handling based on extensive vehicle test driving. I do so because tires do loose pressure through the tire itself over time OR when colder weather may set in in the future.
Also, if you have taken the added expense of having nitrogen gas to inflate your tires with, you can still use compressed air with it to achieve the proper inflation. Nitrogen will not change in pressure as much as compressed natural air due to ambient temperature fluctuations, nor will it escape as easily through the tire rubber over time, hence, tires pressures are more stable, which is why nitrogen is used in the first place.
Also, there is "some school of thought"` about lowering tire pressures (about 4-6 PSI BELOW the recommended pressure) when driving on ice to increase the tire foot print for increased traction and stability. Yes, I must admit, that I have done this with All-Season tires in extreme cases when caught in such a weather driving situation. Did it help? Not sure. Driving slowly, not making sudden steering wheel movements, and gradual brake pressures as needed (even with ABS) probably has a greater impact on driving on ice, as does having a vehicle with All-Wheel Drive and, most of all, having Winter-rated tires versus All-Season tires. Just remember to re-inflate them to the recommended PSI for normal winter driving.
If it has been a while, you should also check the spare tire in the trunk or under the vehicle frame, if it is so equipped. MOST collapsible spare tires require an inflation of 60 PSI to be considered safe for use, and while it is a pain to remove to check and inflate to the proper PSI, its also much bigger "inconvenience" should you need to use it in an emergency in the middle of no-where.
Most vehicles have a tire inflation information placard either in the glove box OR on the driver`s side door sill frame for the OEM tires. If you have a different set of rims and tires than what came with the vehicle, you may need to consult with the tire manufacturer for that vehicle.
Personally, I inflate to about 1 PSI OVER the recommended amount on the placard. Those recommended tire pressures are usually for the best comfort in ride and handling based on extensive vehicle test driving. I do so because tires do loose pressure through the tire itself over time OR when colder weather may set in in the future.
Also, if you have taken the added expense of having nitrogen gas to inflate your tires with, you can still use compressed air with it to achieve the proper inflation. Nitrogen will not change in pressure as much as compressed natural air due to ambient temperature fluctuations, nor will it escape as easily through the tire rubber over time, hence, tires pressures are more stable, which is why nitrogen is used in the first place.
Also, there is "some school of thought"` about lowering tire pressures (about 4-6 PSI BELOW the recommended pressure) when driving on ice to increase the tire foot print for increased traction and stability. Yes, I must admit, that I have done this with All-Season tires in extreme cases when caught in such a weather driving situation. Did it help? Not sure. Driving slowly, not making sudden steering wheel movements, and gradual brake pressures as needed (even with ABS) probably has a greater impact on driving on ice, as does having a vehicle with All-Wheel Drive and, most of all, having Winter-rated tires versus All-Season tires. Just remember to re-inflate them to the recommended PSI for normal winter driving.
Gee, the stuff I`ve forgotten since my, uhm.. school daze 
