GMC 2009 Envoy Denali Owner's Manual page 363

For additional information regarding how much
weight your vehicle can carry, and an example
of the Tire and Loading Information label,
see Loading the Vehicle on page 4-31. How you
load your vehicle affects vehicle handling and
ride comfort. Never load your vehicle with more
weight than it was designed to carry.
When to Check
Check your tires once a month or more.
Do not forget to check the pressure of the spare
tire, if the vehicle has one. See Spare Tire on
page 5-102 for additional information.
How to Check
Use a good quality pocket-type gage to check tire
pressure. You cannot tell if your tires are properly
inflated simply by looking at them. Radial tires
may look properly inflated even when they are
underinflated. Check the tire's inflation pressure
when the tires are 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
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.
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