2007 GMC SIERRA Owner's Manual

C-3500 Extended
Cab (2WD)*Axle Ratio Maximum Trailer Weight GCWR
6.0L V8 3.73 12,200 lbs (5 534 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear
Wheels)3.73 12,000 lbs (5 443 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs
(1 587 kg) maximum.
*Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch.
C-3500 Crew
Cab (2WD)*Axle Ratio Maximum Trailer Weight GCWR
6.0L V8 3.73 12,100 lbs (5 488 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear
Wheels)3.73 11,800 lbs (5 352 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs
(1 587 kg) maximum.
*Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch.
K-3500 Regular
Cab (4WD)*Axle Ratio Maximum Trailer Weight GCWR
6.0L V8 3.73 12,400 lbs (5 624 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear
Wheels)3.73 12,200 lbs (5 534 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs
(1 587 kg) maximum.
*Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch.
457

K-3500 Extended
Cab (4WD)* Axle RatioMaximum Trailer Weight GCWR
6.0L V8 3.73 12,000 lbs (5 443 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear
Wheels)3.73 11,700 lbs (5 307 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs
(1 587 kg) maximum.
*Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch.
K-3500 Crew
Cab (4WD)*Axle Ratio Maximum Trailer Weight GCWR
6.0L V8 3.73 11,800 lbs (5 352 kg) 18,500 lbs (8 391 kg)
6.0L V8 (Dual Rear
Wheels)3.73 11,600 lbs (5 262 kg) 18,500 lbs (8 391 kg)
*Fifth-wheel or gooseneck kingpin weight should be 15 percent to 25 percent of trailer weight up to 3,500 lbs
(1 587 kg) maximum.
*Trailer rating limited to 13,000 lbs (5 897 kg) with weight distributing hitch.
458

The Gross Combination Weight Rating (GCWR) is
the total allowable weight of the completely
loaded vehicle and trailer including any
passengers, cargo, equipment and conversions.
The GCWR for your vehicle should not be
exceeded.
You can ask your dealer for our trailering
information or advice, or you can write us at our
Customer Assistance Offices. SeeCustomer
Assistance Offices on page 648for more
information.Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important
weight to measure because it affects the total
or gross weight of your vehicle. The Gross Vehicle
Weight (GVW) includes the curb weight of the
vehicle, any cargo you may carry in it, and
the people who will be riding in the vehicle. If you
have a lot of options, equipment, passengers
or cargo in your vehicle, it will reduce the tongue
weight your vehicle can carry, which will also
reduce the trailer weight your vehicle can tow. And
if you will tow a trailer, you must add the tongue
load to the GVW because your vehicle will be
carrying that weight, too. SeeLoading Your
Vehicle on page 425for more information about
your vehicle’s maximum load capacity.
459

The trailer tongue weight (A) should be 10 percent
to 15 percent of the total loaded trailer weight, up to
a maximum of 600 lbs (272 kg) for the 1500 or
2500 series, and up to a maximum of 750 lbs
(340 kg) for the 2500 HD or 3500 series with a
weight carrying hitch. The trailer tongue weight (A)
should be 10 percent to 15 percent of the total
loaded trailer weight, up to a maximum of 1,000 lbs
(453 kg) for the 1500 series and up to a maximum
of 1,500 lbs (680 kg) for the 2500, 2500 HD or
3500 series with a weight distributing hitch.Fifth wheel or gooseneck kingpin weight should be
15 to 25 percent of the trailer weight up to the
maximum amount specied in the trailering chart
for your vehicle. See “Weight of the Trailer”,
and “Fifth-Wheel and Gooseneck Trailering” in this
section.
Do not exceed the maximum allowable tongue
weight for your vehicle. Choose the shortest hitch
extension that will position the hitch ball closest
to the vehicle. This will help reduce the effect
of trailer tongue weight on the rear axle.
After you have loaded the trailer, weigh the trailer
and then the tongue separately, to see if the
weights are proper. If they are not, you may be
able to get them right by moving some items
around in the trailer.
Trailering may be limited by the vehicle’s ability to
carry tongue weight. Tongue weight cannot
cause the vehicle to exceed the GVWR (Gross
Vehicle Weight Rating) or the RGAWR (Rear
Gross Axle Weight Rating). The effect of additional
weight may reduce your trailering capacity more
than the total of the additional weight.
460

Consider the following example:
A vehicle model base weight is 5,500 lbs
(2 495 kg); 2,800 lbs (1 270 kg) at the front axle
and 2,700 lbs (1 225 kg) at the rear axle. It
has a GVWR of 7,200 lbs (3 266 kg), a RGAWR
of 4,000 lbs (1 814 kg) and a GCWR (Gross
Combination Weight Rating) of 14,000 lbs
(6 350 kg). The trailer rating should be:
You can expect tongue weight to be at least
10 percent of trailer weight (850 lbs (386 kg)) and
because the weight is applied well behind the rear
axle, the effect on the rear axle will be greater than
just the weight itself, as much as 1.5 times as much.
The weight at the rear axle could be 850 lbs
(386 kg) X 1.5 = 1,275 lbs (578 kg). Since the rear
axle already weighs 2,700 lbs (1 225 kg), adding
1,275 lbs (578 kg) brings the total to 3,975 lbs
(1 803 kg).This is very close to, but within the limit for RGAWR
as well. The vehicle is set to trailer up to 8,500 lbs
(3 856 kg).
But let’s say your specic vehicle is equipped with
some of the latest options and you have a front
seat passenger and two rear seat passengers with
some luggage and gear in the vehicle as well.
You may add 300 lbs (136 kg) to the front
axle weight and 400 lbs (181 kg) to the rear axle
weight. Your vehicle now weighs:
Weight is still below 7,200 lbs (3 266 kg) and you
may think that you should subtract 700 additional
pounds (318 kg) from your trailering capacity
to stay within GCWR limits. Your maximum trailer
would only be 7,800 lbs (3 538 kg). You may
go further and think you must limit tongue weight
to less than 1,000 lbs (454 kg) to avoid
exceeding GVWR.
461

But, you must still consider the effect on the rear
axle. Because your rear axle now weighs 3,100 lbs
(1 406 kg), you can only put 900 lbs (408 kg) on the
rear axle without exceeding RGAWR. The effect of
tongue weight is about 1.5 times the actual weight.
Dividing the 900 lbs (408 kg) by 1.5 leaves you with
being able to handle only 600 lbs (272 kg) of tongue
weight. Since tongue weight is usually at least
10 percent of total loaded trailer weight, you can
expect that the largest trailer your vehicle can
properly handle is 6,000 lbs (2 721 kg).
It is important that you make sure your vehicle
does not exceed any of its ratings — GCWR,
GVWR, RGAWR, Maximum Trailer Rating
or Tongue Weight. The only way to be sure you
are not exceeding any of these ratings is to weigh
your vehicle and trailer.Total Weight on Your Vehicle’s Tires
Be sure your vehicle’s tires are inated to the
upper limit for cold tires. You’ll nd these numbers
on the Certication label at the rear edge of the
driver’s door or see Loading Your Vehicle for more
information. Then be sure you don’t go over the
GVW limit for your vehicle, or the GAWR, including
the weight of the trailer tongue. If you use a
weight distributing hitch, make sure you don’t go
over the rear axle limit before you apply the weight
distribution spring bars.
Hitches
It’s important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads
are a few reasons why you’ll need the right hitch.
462

Weight-Distributing Hitches and Weight
Carrying Hitches
A. Body to Ground Distance
B. Front of Vehiclet
When using a weight-distributing hitch, the hitch
must be adjusted so the distance (A) remains
the same both before and after coupling the trailer
to the tow vehicle.If you use a step-bumper hitch, the bumper could
be damaged in sharp turns. Make sure there is
ample room when turning to avoid contact between
the trailer and the bumper.
If you will be pulling a trailer that, when loaded,
will weigh more than 5,000 lbs (2 270 kg) be sure
to use a properly mounted weight-distributing
hitch and sway control of the proper size.
This equipment is very important for proper vehicle
loading and good handling when driving. Always
use a sway control if the trailer will weigh
more than these limits. You can ask a hitch dealer
about sway controls.
Fifth Wheel and Gooseneck Trailering
Fifth wheel and gooseneck trailers can be
used with many pickup models. These trailers
place a larger percentage of the weight (kingpin
weight) on the tow vehicle than conventional
trailers. Make sure this weight does not cause the
vehicle to exceed GAWR or GVWR.
Fifth wheel or gooseneck kingpin weight should be
15 to 25 percent of the trailer weight up to the
maximum amount specied in the trailering chart
for your vehicle. See “Weight of the Trailer” in
this section for more information.
463

The hitch should be located in the pickup bed so
that it’s centerline is over or slightly in front of the
rear axle. Take care that it is not so far forward that
it will contact the back of the cab in sharp turns.
This is especially important for short box pickups.
Trailer pin box extensions and sliding fth wheel
hitch assemblies can help this condition. There
should be at least six inches of clearance between
the top of the pickup box and the bottom of the
trailer shelf that extends over the box.
Make sure the hitch is attached to the tow vehicle
frame rails. Do not use the pickup box for support.
Safety Chains
You should always attach chains between your
vehicle and your trailer. Cross the safety chains
under the tongue of the trailer to help prevent the
tongue from contacting the road if it becomes
separated from the hitch. Instructions about safety
chains may be provided by the hitch manufacturer
or by the trailer manufacturer. If you are towing a
trailer up to 5,000 lbs (2 271 kg) with a
factory-installed step bumper, you may attach the
safety chains to the attaching points on the bumper.If you are towing a trailer up to your vehicle’s trailer
rating limit you may attach the safety chains to the
attaching point on the hitch platform. If you are
towing with an aftermarket hitch follow the trailer or
hitch manufacturer’s recommendation for attaching
safety chains. Always leave just enough slack so
you can turn with your rig. Never allow safety
chains to drag on the ground.
Trailer Brakes
If your trailer weighs more than 2,000 lbs (900 kg)
loaded, then it needs its own brakes – and they
must be adequate. Be sure to read and follow the
instructions for the trailer brakes so you’ll be
able to install, adjust and maintain them properly.
If your vehicle is equipped with StabiliTrak
®,
your trailer cannot tap into the vehicle’s hydraulic
brake system.
464