GMC 2011 Sierra Owner's Manual page 327

Here is an example of proper
truck and camper match:
Camper Center of Gravity
A.
Recommended Center of
B.
Gravity Location Zone
When the truck is used to carry
a slide in camper, the total cargo
load of the truck consists of the
manufacturer's camper weight
figure, the weight of installed
additional camper equipment not
included in the manufacturer's
camper weight figure, the weight
of camper cargo, and the weight
of passengers in the camper.
The total cargo load should
not exceed the truck's cargo
weight rating, and the camper's
center of gravity (A) should fall
within the truck's recommended
center of gravity zone (B) when
installed.
Any accessories or other
equipment that are added to
the vehicle must be weighed.
Then, subtract this extra weight
from the CWR. This extra weight
may shorten the center of
gravity zone of the vehicle.
If the slide-in camper and its
load weighs less than the CWR,
the center of gravity zone for
your vehicle may be larger.
Secure loose items to prevent
weight shifts that could affect
the balance of the vehicle.