1999 Oldsmobile Alero Owner's Manual - Page 260

yellowblue NOTICE: (Continued) If your tires have too much air (overinflation), you can get the following: D Unusual wear D Bad handling D Rough ride D Needless damage from road hazards. When to Check Check your tires once a month or more. Don't forget your compact spare tire. It should be at 60 psi (420 kPa). How to Check Use a good quality pocket-type gage to check tire pressure. You can't tell if your tires are properly inflated simply by looking at them. Radial tires may look properly inflated even when they're underinflated. Be sure to put the valve caps back on the valve stems. They help prevent leaks by keeping out dirt and moisture. Tire Pressure Monitor System (If Equipped) The tire pressure monitor system can alert you to a large change in the pressure of one tire. The system "learns" the pressure at each tire throughout the operating speed range of your vehicle. The system normally takes between 45 and 90 minutes of driving to learn the tire pressures. This time may be longer depending on your individual driving habits. Learning need not be accumulated during a single trip. Once learned, the system will remember the tire pressures until the system is recalibrated. After the system has learned tire pressures with properly inflated tires, the LOW TIRE PRESSURE light will come on if the pressure in one tire becomes 12 psi (83 kPa) lower than the other three tires. The tire pressure monitor system won't alert you if the pressure in more than one tire is low, if the system is not properly calibrated, or if the vehicle is moving at less than 15 mph (25 km/h), faster than 75 mph (120 km/h) on rough roads or during turns. The light may also come on if you are driving on partially cleared pavement. The tire pressure monitor system detects differences in tire rotation speeds that are caused by changes in tire pressure. The system can alert you about a low tire -- but it doesn't replace normal tire maintenance. See "Tires" in the Index. 6-36