2007 HUMMER H2 Owners Manual

Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig.
For example, speed, altitude, road grades, outside
temperature and how much your vehicle is used
to pull a trailer are all important. It can also depend
on any special equipment that you have on your
vehicle, and the amount of tongue weight the
vehicle can carry. See “Weight of the Trailer
Tongue” later in this section for more information.Maximum trailer weight is calculated assuming
only the driver is in the tow vehicle and it has all
the required trailering equipment. The weight
of additional optional equipment, passengers and
cargo in the tow vehicle must be subtracted
from the maximum trailer weight.
Use the following chart to determine how much
your vehicle can weigh, based upon your vehicle
model and options.
Engine Axle Ratio Maximum Trailer Weight **GCWR
6000 V8 (SUV) 4.10 6,700 lbs (3 039 kg) 13,500 lbs (6 123 kg)
6000 V8 (SUT)* 4.10 6,600 lbs (2 994 kg) 13,500 lbs (6 123 kg)
**The Gross Combination Weight Rating (GCWR) in 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.
*Sport utility truck (SUT) models are neither designed nor intended to tow 5th wheel or gooseneck trailers.
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 540for more
information.
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Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important
weight to measure because it affects the total
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. 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 362for more information about your vehicle’s
maximum load capacity.The trailer tongue weight (A) should be 10 percent
to 15 percent of the total loaded trailer weight (B),
up to a maximum of 500 lbs (227 kg) with a weight
carrying hitch. The trailer tongue weight (A) should
be 10 percent to 15 percent of the total loaded
trailer weight (B), up to a maximum of
700 lbs (318 kg) with a weight distributing hitch.
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.
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Your spare tire carrier is behind the tailgate.
If your hitch extension is too short, the spare tire
may interfere with trailer coupling or trailer
tongue jack operation on some types of trailers.
After you’ve loaded your trailer, weigh the
trailer and then the tongue, separately, to see if
the weights are proper. If they aren’t, you may be
able to get them right simply by moving some
items around in the trailer.
Trailering may also 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.
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).
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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. 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 isabout 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 seeLoading Your Vehicle on
page 362. 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.
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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.
Weight-Distributing Hitches and Weight
Carrying Hitches
When using a weight-distributing hitch, the hitch
must be adjusted so that the distance (A) remains
the same both before and after coupling the
trailer to the tow vehicle.If you will be pulling a trailer that, when loaded,
will weigh more than 5,000 lbs (2 268 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.
You should always use a sway control if your
trailer will weigh more than these limits. You can
ask a hitch dealer about sway controls.
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. Always leave just enough
slack so you can turn with your rig. Never allow
safety chains to drag on the ground.
(A) Body-to-Ground Distance (B) Front of Vehicle
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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.
Your trailer brake system can tap into the
vehicle’s hydraulic brake system only if:
The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
The trailer’s brake system will use less than
0.02 cubic inch (0.3 cc) of uid from your
vehicle’s master cylinder. Otherwise,
both braking systems won’t work well.
You could even lose your brakes.
If everything checks out this far, make the brake
tap at the port on the master cylinder that
sends the uid to the rear brakes. But don’t use
copper tubing for this. If you do, it will bend
and nally break off. Use steel brake tubing.
Driving with a Trailer
Towing a trailer requires a certain amount of
experience. Before setting out for the open road,
you’ll want to get to know your rig. Acquaint
yourself with the feel of handling and braking with
the added weight of the trailer. And always
keep in mind that the vehicle you are driving is
now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector,
lamps, tires and mirror adjustment. If the trailer has
electric brakes, start your vehicle and trailer
moving and then apply the trailer brake controller
by hand to be sure the brakes are working.
This lets you check your electrical connection at
the same time.
During your trip, check occasionally to be sure
that the load is secure, and that the lamps and any
trailer brakes are still working.
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Following Distance
Stay at least twice as far behind the vehicle ahead
as you would when driving your vehicle without
a trailer. This can help you avoid situations
that require heavy braking and sudden turns.
Passing
You’ll need more passing distance up ahead when
you’re towing a trailer. Because you’re a good
deal longer, you’ll need to go much farther beyond
the passed vehicle before you can return to
your lane.
Backing Up
Hold the bottom of the steering wheel with one
hand. Then, to move the trailer to the left,
just move that hand to the left. To move the trailer
to the right, move your hand to the right. Always
back up slowly and, if possible, have someone
guide you.
Making Turns
Notice:Making very sharp turns while
trailering could cause the trailer to come in
contact with the vehicle. Your vehicle could be
damaged. Avoid making very sharp turns
while trailering.
When you’re turning with a trailer, make wider
turns than normal. Do this so your trailer
won’t strike soft shoulders, curbs, road signs,
trees or other objects. Avoid jerky or sudden
maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
The arrows on your instrument panel will
ash whenever you signal a turn or lane change.
Properly hooked up, the trailer lamps will also
ash, telling other drivers you’re about to
turn, change lanes or stop.
When towing a trailer, the arrows on your
instrument panel will ash for turns even if the
bulbs on the trailer are burned out. Thus, you may
think drivers behind you are seeing your signal
when they are not. It’s important to check
occasionally to be sure the trailer bulbs are still
working.
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Driving On Grades
Reduce speed and shift to a lower gearbefore
you start down a long or steep downgrade. If you
don’t shift down, you might have to use your
brakes so much that they would get hot and no
longer work well.
You can tow in DRIVE (D). You may want to shift
the transmission to THIRD (3) or, if necessary,
a lower gear selection if the transmission shifts too
often (e.g., under heavy loads and/or hilly
conditions).
You may also want to activate the tow/haul mode
if the transmission shifts too often. See “Tow/Haul
Mode” earlier.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If you
turn your engine off immediately after towing at high
altitude on steep uphill grades, your vehicle may
show signs similar to engine overheating. To avoid
this, let the engine run while parked (preferably on
level ground) with the automatic transmission in
PARK (P) for a few minutes before turning the
engine off. If you do get the overheat warning,
seeEngine Overheating on page 418.
Parking on Hills
{CAUTION:
You really should not park your
vehicle, with a trailer attached, on a hill.
If something goes wrong, your rig could
start to move. People can be injured, and
both your vehicle and the trailer can be
damaged.
But if you ever have to park your rig on a hill,
here’s how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release
the regular brakes until the chocks absorb
the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P).
5. Release the regular brakes.
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