1997 GMC Suburban Owner's Manual - Page 328

How to Check NOTICE: Don't let anyone tell you that underinflation or overinflation is all right.It's not. If your tires don't have enough air (underinflation), can you get thefollowing: Too much flexing Too much heat Tireoverloading Bad wear Badhandling Bad fuel economy. If your tires have too much air (overinflation), you can get the following: Unusualwear 0 Badhandling 0 Roughride 0 Needless damage from road hazards. When to Check Check your tires once a month or more. Also, check the tire pressure of the spare tire. 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 the valve stems. on They help prevent leaksby keeping out dirt and moisture. Tire Inspection and Rotation Tires should be rotated every 6,000 to 8,000 miles ( 10 000 to 13 000 km). Any time you notice unusual wear, rotate your tires as soon as possible and check wheel alignment. Also check for damaged tires or wheels. See "When It's Time for New Tires" and "Wheel Replacement'' later in this section for more information. The purpose of regular rotation is to achieve more uniform wear for all tires on the vehicle. The first rotation is the most important. See "Scheduled Maintenance Services" in the Index for scheduled rotation intervals. 6-46