GMC 2006 Sierra 1500 Pickup Owner's Manual page 363

Certification/Tire Label
A vehicle specific Certification/Tire label is found on
the rear edge of the driver's door. The label shows the
size of your vehicle's original tires and the inflation
pressures needed to obtain the gross weight capacity
of your vehicle. This is called Gross Vehicle Weight
Rating (GVWR). The GVWR includes the weight of
the vehicle, all occupants, fuel, and cargo.
The Certification/Tire label also tells you the maximum
weights for the front and rear axles, called Gross Axle
Weight Rating (GAWR). To find out the actual loads on
your front and rear axles, you need to go to a weigh
station and weigh your vehicle. Your dealer can help you
with this. Be sure to spread out your load equally on both
sides of the centerline.
Never exceed the GVWR for your vehicle, or the GAWR
for either the front or rear axle.
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