The proper cold inflation of the tires on your professional vehicle depends on the type of tires on it.
| • | If your vehicle has P235/60R17 XL size tires, the cold inflation pressure is 41 psi (284 kPa). |
| • | If your vehicle has Goodyear LT235/60R17/E size tires, the correct cold inflation pressure depends on the vehicle mass and should be determined by the vehicle coach-builder. A label on the side of the driver's door should state the proper cold inflation pressures. If the final stage manufacturer's label is not present, the coach-builder should be consulted. Do not use the tire pressures indicated on the General Motors label. These tire pressures are for the incomplete vehicle and are not the correct tire pressures for the completed professional vehicle. |
Operation at inflation pressures below this recommendation may cause your tires to become overloaded.
Notice: Failure to maintain proper pressure in front tires may lead to a loss of steering assist and power steering pump failure.
Caution: Poorly maintained and improperly used tires are dangerous.
• Overloading your tires can cause overheating as a result of too much
friction. You could have an air-out and a serious accident. See "Loading Your
Vehicle" in the Index of your DeVille owner's manual. • Underinflated tires pose the same danger as overloaded tires. The resulting
accident could cause serious injury. Check all tires frequently to maintain the recommended
pressure. Tire pressure should be checked when your tires are cold. • Overinflated tires are more likely to be cut, punctured or broken by
a sudden impact - such as when you hit a pothole. Keep tires at the recommended
pressure. • Worn, old tires can cause accidents. If your tread is badly worn, or
if your tires have been damaged, replace them.
The Tire and Loading Information label, shows the correct inflation pressures for your tires when they're cold. "Cold" means your vehicle has been sitting for at least three hours or driven no more than 1 mile (1.6 km). See Loading the Vehicle for more information on the Tire and Loading Information label.
If you'll be driving at high speeds (e.g., speeds of 100 mph (160 km/h) or higher), where it is legal, set the cold inflation pressure to the maximum inflation pressure shown on the tire sidewall, or to 38 psi (265 kPa), whichever is lower. See the example below. When you end this high-speed driving, return to the cold inflation pressure shown on the Tire and Loading Information label.
Example:
You'll find maximum load and inflation pressure molded on the tire's sidewall, in small letters, near the rim flange. It will read something like this: Maximum load 690 kg (1521 lbs) @ 300 kPa (44 psi) Max. Press.
For this example, you would set the inflation pressure for high-speed driving at 38 psi (265 kPa).
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), you can get the following:
• Too much flexing • Too much heat • Tire overloading • Bad wear • Bad handling • Bad fuel economy • Unusual wear • Bad handling • Rough ride • Needless damage from road hazards
When to Check
Check your tires once a month or more.
Do not 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. Check tire inflation pressure when the tire is cold. Cold means your vehicle has been sitting for at least three hours or driven no more than 1 mile (1.6 km).
Remove the valve cap from the tire valve stem. Press the tire gage firmly onto the valve to get a pressure measurement. If the cold tire inflation pressure matches the recommended pressure on the Tire and Loading Information label, no further adjustment is necessary. If the inflation pressure is low, add air until you reach the recommended amount.
If you overfill the tire, release air by pushing on the metal stem in the center of the tire valve. Recheck the tire pressure with the tire gage.
Be sure to put the valve caps back on the valve stems. They help prevent leaks by keeping out dirt and moisture.
Your vehicle has a Tire Pressure Monitor (TPM) that sends tire pressure information to the Driver Information Center (DIC). Using the DIC control buttons, the driver is able to check tire pressure levels in all four road tires. See Tire Pressure Monitor Operation and DIC Controls and Displays for additional information.
