1994 GMC Suburban Owner's Manual - Page 309

You can operate some vehicles at reduced inflation pressures only when you'll be carrying reduced loads. On those vehicles, the minimum cold inflation pressures for atypical reduced load are printed the "Improved on Ride Tire Pressure"label located on the driver's door. Weigh the vehicle to find the load on each tire and see the label for the minimum cold inflation Dressures for that load. NOTICE: Don't let anyone tell you that underinflation or overinflation is all right. It's not. If your tires don't have enoughair (underinflation) you can get: Too much flexing Too much heat Tire overloading Bad wear Bad handling Bad fuel economy. If your tires have too muchair (overinflation),you can get: Unusual wear Bad handling Rough ride 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. How to Check Use a good quality pocket-type gage to check tire pressure. Simply looking at the tires will not tell you the pressure, especially if you have radial tires - which may look properly inflated even if they're underinflated. If your tires have valve caps,be sure to put them back on. They help prevent leaks by keeping out dirt and moisture. 6-63