GMC 2006 Envoy Owner's Manual page 336

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.
4-48
This is called Gross Vehicle Weight Rating (GVWR). The
GVWR includes the weight of the vehicle, all occupants,
fuel, cargo, and trailer tongue weight, if pulling a trailer.
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.
And, if you do have a heavy load, you should spread
it out.
Similar appearing vehicles may have different GVWRs
and capacity weights. Please note your vehicle's
Certification/Tire label or consult your dealer for
additional details.