GMC SIERRA CLASSIC 2007 Owners Manual

Item Description Total
AVehicle Capacity
Weight for Example 1=1,000 lbs (453 kg)
BSubtract
Occupant Weight
150 lbs (68 kg)×2=300 lbs (136 kg)
CAvailable Occupant
and Cargo Weight=700 lbs (317 kg)Item Description Total
AVehicle Capacity
Weight for Example 2=1,000 lbs (453 kg)
BSubtract
Occupant Weight
150 lbs (68 kg)×5=750 lbs (136 kg)
CAvailable Cargo
Weight=250 lbs (113 kg) Example 1
Example 2
411

Item Description Total
AVehicle Capacity Weight
for Example 3=1,000 lbs (453 kg)
BSubtract Occupant
Weight 200 lbs
(91 kg)×5=1000 lbs (453 kg)
CAvailable Cargo Weight
=0 lbs (0 kg)
Refer to your vehicle’s tire and loading
information label for specic information about
your vehicle’s capacity weight and seating
positions. The combined weight of the driver,
passengers, and cargo should never exceed your
vehicle’s capacity weight.
Certication/Tire Label
A vehicle specic Certication/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 ination 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 Certication/Tire label also tells you the
maximum weights for the front and rear axles,
called Gross Axle Weight Rating (GAWR).
Example 3
412

To nd 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.
The Certication/Tire label also contains important
information about your Front Axle Reserve
Capacity. See “What is front axle reserve capacity,
and how do I calculate it?” underAdding a Snow
Plow or Similar Equipment on page 416.
{CAUTION:
In the case of a sudden stop or collision,
things carried in the bed of your truck
could shift forward and come into the
passenger area, injuring you and others.
If you put things in the bed of your truck,
you should make sure they are properly
secured.
{CAUTION:
Do not load your vehicle any heavier than
the Gross Vehicle Weight Rating (GVWR),
or either the maximum front or rear Gross
Axle Weight Rating (GAWR). If you do,
parts on your vehicle can break, and it
can change the way your vehicle handles.
These could cause you to lose control
and crash. Also, overloading can shorten
the life of your vehicle.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
Using heavier suspension components to get
added durability might not change your weight
ratings. Ask your dealer to help you load
your vehicle the right way.
413

If you put things inside your vehicle — like
suitcases, tools, packages, or anything
else — they go as fast as the vehicle goes.
If you have to stop or turn quickly, or if there
is a crash, they will keep going.
{CAUTION:
Things you put inside your vehicle can
strike and injure people in a sudden stop
or turn, or in a crash.
Put things in the cargo area of your
vehicle. Try to spread the weight
evenly.
Never stack heavier things, like
suitcases, inside the vehicle so that
some of them are above the tops of
the seats.
CAUTION: (Continued)
CAUTION: (Continued)

Do not leave an unsecured child
restraint in your vehicle.
When you carry something inside the
vehicle, secure it whenever you can.
Do not leave a seat folded down
unless you need to.
There is also important loading information for
off-road driving in this manual. See “Loading Your
Vehicle for Off-Road Driving“ underOff-Road
Driving on page 372.
414

Two-Tiered Loading
By positioning four 2 inches (5 cm) by 6 inches
(15 cm) wooden planks across the width of
the pickup box, you can create an upper load
platform. The planks must be inserted in the pickup
box depressions. The length of the planks must
allow for at least a 3/4 inch (2 cm) bearing surface
on each end of the plank.
When using this upper load platform, be sure the
load is securely tied down to prevent it from
shifting. The load’s center of gravity should be
positioned in a zone over the rear axle. The zone
is located in the area between the front of each
wheel well and the rear of each wheel well.
The center of gravity height must not extend above
the top of the pickup box areboard.
Any load that extends beyond the vehicle’s
taillamp area must be properly marked according
to local laws and regulations.
Remember not to exceed the Gross Axle Weight
Rating (GAWR) of the front or rear axle.
Add-On Equipment
When you carry removable items, you may need
to put a limit on how many people you carry
inside your vehicle. Be sure to weigh your vehicle
before you buy and install the new equipment.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
Remember not to exceed the Gross Axle Weight
Rating (GAWR) of the front or rear axle.
*Equipment Maximum Weight
Ladder Rack and Cargo 750 lbs (340 kg)
Cross Toolbox and Cargo 400 lbs (181 kg)
Side Boxes and Cargo 250 lbs per side
(113 kg per side)
*The combined weight for all rail-mounted equipment
should not exceed 1,000 lbs (454 kg), excluded
1500 crew cab models with 5 ft 8 in (173 cm) box
length. A reinforcement kit for rail-mounted add-on
equipment is recommended. See your dealer.
Ladder racks are not recommended for 1500 crew
cab models with 5 ft 8 in (173 cm) pick-up box length.
Maximum recommended cross-mounted toolbox and
cargo weight is 300 lbs (136 kg) for the 1500 crew
cab with 5 ft 8 in (173 cm) pick-up box length.
415

Adding a Snow Plow or Similar
Equipment
Before installing a snow plow on your vehicle,
here are some things you will need to know:
Notice:If your vehicle does not have the
snow plow prep package, adding a plow can
damage your vehicle, and the repairs would not
be covered by warranty. Unless your vehicle
was built to carry a snow plow, do not add one
to your vehicle. If your vehicle has the snow
plow prep package, called RPO VYU, then
the payload your vehicle can carry will
be reduced when a snow plow is installed.
Your vehicle can be damaged if either the front
or rear axle ratings or the Gross Vehicle
Weight (GVW) are exceeded.
Q:How do I know if my vehicle can handle a
snow plow?
A:Some vehicles are built with a special snow
plow prep package, called RPO VYU. If your
vehicle has this option, you can add a
plow to it, provided certain weights, such as
the weights on the vehicle’s axles and
the Gross Vehicle Weight (GVW), are not
exceeded.
Q:How heavy can a snow plow safely be?
A:The plow your vehicle can carry depends on
many things, such as:
The options your vehicle came with, and the
weight of those options.
The weight and number of passengers you
intend to carry.
The weight of items you have added to your
vehicle, like a tool box or truck cap.
The total weight of any additional cargo you
intend to carry.
416

Say, for example, you have a 700 lb (318 kg)
snow plow. The total weight of all occupants and
cargo inside the cab should not exceed 300 lb
(135 kg). This means that you may only be able to
carry one passenger. But, even this may be too
much if you have got other equipment already
adding to the weight of your vehicle.
Here are some guidelines for safely carrying a
snow plow on your vehicle:
Make sure the weight on the front and
rear axles does not exceed the axle rating
for each.
For the front axle, if more cargo or passengers
must be carried, appropriate counter ballast
must be installed rear of the rear axle. Counter
ballast must be properly secured so it will
not move during driving.
Follow the snow plow manufacturer’s
recommendations regarding rear ballast.
Rear ballast may be required to ensure
a proper front and rear weight distribution
ratio, even though the actual weight at
the front axle may be less than the front
axle rating.
The snow plow manufacturer or installer can
assist you in determining the amount of rear
ballast required, to help make sure your
snowplow/vehicle combination does not
exceed the GVW rating, the front and rear
axle ratings, and the front and rear weight
distribution ratio.
The total vehicle must not exceed the
GVW rating.
417

Q:What is front axle reserve capacity, and
how do I calculate it?
A:Front axle reserve capacity is the difference
between your front Gross Axle Weight Rating
(GAWR) and the front axle weight of your
vehicle with full fuel and passengers. Basically,
it is the amount of weight you can add to your
front axle before reaching your front GAWR.
The front axle reserve capacity for your vehicle
can be found in the lower right corner of the
Certication/Tire label, as shown.In order to calculate the amount of weight any
front accessory, such as a snow plow, is adding to
the front axle, use the following formula:
(W x (A + W.B.)) /W.B.= Weight the accessory is
adding to the front axle.
Where:
W = Weight of added accessory
A = Distance that the accessory is in front of the
front axle
W.B. = Vehicle Wheelbase
United StatesCanada
418

For example, adding a 700 lb (318 kg) snow plow
actually adds more than 700 lbs (318 kg) to the
front axle. Using the formula, if the snow plow
is 4 ft (122 cm) in front of the front axle and the
wheel base is 10 ft (305 cm), then:
W = 700 lb (318 kg)
A = 4 ft (122 cm)
W.B. = 10 ft (305 cm)
(W x (A + W.B.))/W.B. = (700 x (4 + 10))/10 =
980 lbs (445 kg)
So, if your truck’s front axle reserve capacity is
more than 980 lbs (445 kg), you could add
the snow plow without exceeding the front GAWR.
Q:What if I want to add heavier equipment
to my vehicle?
A:You can add heavier equipment on the front
of the vehicle if you compensate for it by
carrying fewer passengers, less cargo, or by
positioning cargo towards the rear. This
has the effect of reducing the load on the front.
However, the front GAWR, rear GAWR, and
the Gross Vehicle Weight Rating (GVWR)
must never be exceeded.
{CAUTION:
On some vehicles that have certain front
mounted equipment, such as a snow
plow, it may be possible to load the front
axle to the front gross axle weight rating
(GAWR) but not have enough weight on
the rear axle to have proper braking
performance. If your brakes can not work
properly, you could have a crash. To help
your brakes work properly when a snow
plow is installed, always follow the snow
plow manufacturer or installer’s
recommendation for rear ballast to ensure
a proper front and rear weight distribution
ratio, even though the actual front weight
may be less than the front GAWR, and the
total vehicle weight is less than the gross
vehicle weight rating (GVWR). Maintaining
a proper front and rear weight distribution
ratio is necessary to provide proper
braking performance.
419

Q:What is total vehicle reserve capacity?
A:This is the difference between your GVWR and
the weight of your truck with full fuel and
passengers. It is the amount of weight you can
add to your vehicle before reaching your
GVWR. Keep in mind that reserve capacity
numbers are intended as a guide when
selecting the amount of equipment or cargo
your truck can carry. If you are unsure of your
vehicle’s front, rear, or total weight, go to a
weigh station and weigh your vehicle.
Your dealer can also help you with this.
The total vehicle reserve capacity for your
vehicle can be found in the lower right corner
of the Certication/Tire label as shown
previously.
See your dealer for additional advice and
information about using a snow plow on your
vehicle. Also, seeLoading Your Vehicle on
page 409.
Emergency Roof Lamp Provisions
Vehicles with the RPO VYU snow plow prep
package also have an emergency roof lamp
provision package, RPO TRW. Wiring for the
emergency roof lamp is provided in the B-pillar as
shown. SeeAuxiliary Roof Mounted Lamp on
page 226for switch location.
A. Body Side Inner Panel
B. Emergency Roof Lamp Harness
420