tires HUMMER H2 2007 User Guide

Crossing Obstacles
Approach Angle — a Key to Mobility
If you encounter a large dip in the terrain, do not
enter straight on; enter at an angle — 15° minimum
approach (A), 75° maximum approach angle (B).
For very large dips, ditches or small washes, coast
in, using the engine as a brake (transmission and
transfer case lowest gears). Then, use the low
ranges in the transmission and transfer case to
power out.
Roll Your Tires Over Large Rocks
Do not straddle large
rocks; drive over them,
letting the tire cover
the rock. The tread of
the tire is thicker
and tougher than the
sidewall of the tire
and is more resilient to
impact than underbody
components.
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Driving Across an Incline
Sooner or later, an off-road trail will probably go
across the incline of a hill. If this happens,
you have to decide whether to try to drive across
the incline. Here are some things to consider:
A hill that can be driven straight up or down
may be too steep to drive across. When you go
straight up or down a hill, the length of the
wheel base — the distance from the front
wheels to the rear wheels — reduces the
likelihood the vehicle will tumble end over end.
But when you drive across an incline, the much
more narrow track width — the distance
between the left and right wheels — may not
prevent the vehicle from tilting and rolling over.
Also, driving across an incline puts more weight
on the downhill wheels. This could cause a
downhill slide or a rollover.
Surface conditions can be a problem when
you drive across a hill. Loose gravel, muddy
spots, or even wet grass can cause your
tires to slip sideways, downhill. If the vehicle
slips sideways, it can hit something that will
trip it — a rock, a rut, etc. — and roll over.
Hidden obstacles can make the steepness of
the incline even worse. If you drive across a
rock with the uphill wheels, or if the downhill
wheels drop into a rut or depression, your
vehicle can tilt even more.
For reasons like these, you need to decide
carefully whether to try to drive across an incline.
Just because the trail goes across the incline
does not mean you have to drive it. The last
vehicle to try it might have rolled over.
{CAUTION:
Driving across an incline that is too steep
will make your vehicle roll over. You could
be seriously injured or killed. If you have
any doubt about the steepness of the
incline, do not drive across it. Find another
route instead.
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Driving in Mud, Sand, Snow, or Ice
When you drive in mud, snow, or sand, your
wheels will not get good traction. You cannot
accelerate as quickly, turning is more difficult, and
you will need longer braking distances.
It is best to use a low gear when you are in
mud —the deeper the mud, the lower the gear.
In really deep mud, the idea is to keep your vehicle
moving so you do not get stuck. Be careful to keep
mud from building up and washing onto the engine
cooling system.
When you drive on sand, you will sense a change
in wheel traction. But it will depend upon how
loosely packed the sand is. On loosely packed
sand, such as on beaches or sand dunes,
your tires will tend to sink into the sand. This has
an effect on steering, accelerating, and braking.
Drive at a reduced speed and avoid sharp turns or
abrupt maneuvers.Hard packed snow and ice offer the worst tire
traction. On these surfaces, it is very easy to lose
control. On wet ice, for example, the traction is
so poor that you will have difficulty accelerating.
And if you do get moving, poor steering and
difficult braking can cause you to slide out of
control.
{CAUTION:
Driving on frozen lakes, ponds, or rivers
can be dangerous. Underwater springs,
currents under the ice, or sudden thaws
can weaken the ice. Your vehicle could
fall through the ice and you and your
passengers could drown. Drive your
vehicle on safe surfaces only.
336

Driving in Water
Heavy rain can mean ash ooding, and ood
waters demand extreme caution.
Find out how deep the water is before you drive
through it. If it is deep enough to cover your wheel
hubs, axles, or exhaust pipe, do not try it — you
probably will not get through. Also, water that deep
can damage your axle and other vehicle parts.
Your vehicle is capable of depths up to 20 inches.
Know how to judge whether the water is deeper
than this before proceeding into it.
If the water is not too deep, drive slowly through it.
At faster speeds, water splashes on your ignition
system and your vehicle can stall. Stalling can also
occur if you get your tailpipe under water. And,
as long as your tailpipe is under water, you
will never be able to start your engine. When you
go through water, remember that when your
brakes get wet, it may take you longer to stop.{CAUTION:
Driving through rushing water can be
dangerous. Deep water can sweep your
vehicle downstream and you and your
passengers could drown. If it is only
shallow water, it can still wash away the
ground from under your tires, and you
could lose traction and roll the vehicle
over. Do not drive through rushing water.
SeeDriving in Rain and on Wet Roads on
page 344for more information on driving
through water.
337

After Off-Road Driving
Remove any brush or debris that has collected
on the underbody, chassis, or under the hood.
These accumulations can be a re hazard.
After operation in mud or sand, have the brake
linings cleaned and checked. These substances
can cause glazing and uneven braking. Check the
engine and oil coolers for mud accumulation.
Thoroughly and carefully clean these devices to
allow proper cooling. Check the body structure,
steering, suspension, wheels, tires, and exhaust
system for damage. Also, check the fuel lines and
cooling system for any leakage.
Your vehicle will require more frequent service
due to off-road use. See the Maintenance
Schedule for additional information.
Assist Steps
Your vehicle may be equipped with removable
side steps.
Remove the steps prior to off-roading to give your
vehicle more ground clearance and to prevent
damage to the vehicle from the side steps
dragging and/or catching on obstacles.
Notice:Do not drive off-road with the side
steps attached to your vehicle. You can damage
the side steps and/or your vehicle’s frame if
they get caught or drag against an obstacle.
This damage would not be covered by your
vehicle’s warranty. Always remove the side
steps prior to any off-road driving.
338

Driving in Rain and on Wet Roads
Rain and wet roads can mean driving trouble. On a
wet road, you cannot stop, accelerate, or turn as
well because your tire-to-road traction is not as
good as on dry roads. And, if your tires do not have
much tread left, you will get even less traction.It is always wise to go slower and be cautious if rain
starts to fall while you are driving. The surface may
get wet suddenly when your reexes are tuned for
driving on dry pavement.
The heavier the rain, the harder it is to see. Even if
your windshield wiper blades are in good shape, a
heavy rain can make it harder to see road signs and
traffic signals, pavement markings, the edge of the
road, and even people walking.
It is wise to keep your wiping equipment in good
shape and keep your windshield washer uid
reservoir lled with washer uid. Replace
your windshield wiper inserts when they show
signs of streaking or missing areas on the
windshield, or when strips of rubber start to
separate from the inserts.
344

{CAUTION:
Wet brakes can cause accidents. They may
not work as well in a quick stop and may
cause pulling to one side. You could lose
control of the vehicle.
After driving through a large puddle of
water or a car wash, apply your brake pedal
lightly until your brakes work normally.
Driving too fast through large water puddles or
even going through some car washes can cause
problems, too. The water may affect your brakes.
Try to avoid puddles. But if you cannot, try to slow
down before you hit them.
Hydroplaning
Hydroplaning is dangerous. So much water can
build up under your tires that they can actually ride
on the water. This can happen if the road is wet
enough and you are going fast enough. When your
vehicle is hydroplaning, it has little or no contact
with the road.
Hydroplaning does not happen often. But it can
if your tires do not have much tread or if the
pressure in one or more is low. It can happen if a
lot of water is standing on the road. If you can
see reections from trees, telephone poles,
or other vehicles, and raindrops dimple the water’s
surface, there could be hydroplaning.
Hydroplaning usually happens at higher speeds.
There just is not a hard and fast rule about
hydroplaning. The best advice is to slow down
when it is raining.
345

Driving Through Deep Standing Water
Notice:If you drive too quickly through deep
puddles or standing water, water can come in
through your engine’s air intake and badly
damage your engine. Never drive through water
that is slightly lower than the underbody of your
vehicle. If you cannot avoid deep puddles or
standing water, drive through them very slowly.
Driving Through Flowing Water
{CAUTION:
Flowing or rushing water creates strong
forces. If you try to drive through owing
water, as you might at a low water
crossing, your vehicle can be carried
away. As little as six inches of owing
water can carry away a smaller vehicle.
CAUTION: (Continued)
CAUTION: (Continued)
If this happens, you and other vehicle
occupants could drown. Do not ignore
police warning signs, and otherwise be
very cautious about trying to drive
through owing water.
Some Other Rainy Weather Tips
Besides slowing down, allow some extra
following distance. And be especially
careful when you pass another vehicle.
Allow yourself more clear room ahead, and
be prepared to have your view restricted
by road spray.
Have good tires with proper tread depth.
SeeTires on page 448.
346

Once you are moving on the freeway, make
certain you allow a reasonable following distance.
Expect to move slightly slower at night.
When you want to leave the freeway, move to the
proper lane well in advance. If you miss your
exit, do not, under any circumstances, stop and
back up. Drive on to the next exit.
The exit ramp can be curved, sometimes quite
sharply. The exit speed is usually posted.
Reduce your speed according to your
speedometer, not to your sense of motion. After
driving for any distance at higher speeds, you may
tend to think you are going slower than you
actually are.
Before Leaving on a Long Trip
Make sure you are ready. Try to be well rested.
If you must start when you are not fresh — such as
after a day’s work — do not plan to make too many
miles that rst part of the journey. Wear comfortable
clothing and shoes you can easily drive in.
Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it is ready to go. If it
needs service, have it done before starting out.Of course, you will nd experienced and able
service experts in GM dealerships all across
North America. They will be ready and willing to
help if you need it.
Here are some things you can check before a trip:
Windshield Washer Fluid:Is the reservoir
full? Are all windows clean inside and outside?
Wiper Blades:Are they in good shape?
Fuel, Engine Oil, Other Fluids:Have you
checked all levels?
Lamps:Are they all working? Are the lenses
clean?
Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough
for long-distance driving? Are the tires
all inated to the recommended pressure?
Weather Forecasts:What is the weather
outlook along your route? Should you
delay your trip a short time to avoid a major
storm system?
Maps:Do you have up-to-date maps?
349

Highway Hypnosis
Is there actually such a condition as highway
hypnosis? Or is it just plain falling asleep at the
wheel? Call it highway hypnosis, lack of
awareness, or whatever.
There is something about an easy stretch of road
with the same scenery, along with the hum of
the tires on the road, the drone of the engine, and
the rush of the wind against the vehicle that
can make you sleepy. Do not let it happen to you!
If it does, your vehicle can leave the road in
less than a second, and you could crash and
be injured.
What can you do about highway hypnosis?
First, be aware that it can happen.Then here are some tips:Make sure your vehicle is well ventilated, with
a comfortably cool interior.
Keep your eyes moving. Scan the road ahead
and to the sides. Check your mirrors and your
instruments frequently.
If you get sleepy, pull off the road into a rest,
service, or parking area and take a nap, get
some exercise, or both. For safety, treat
drowsiness on the highway as an emergency.
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