2011 GMC SIERRA tires

Black plate (3,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-3
Death and injury associated with
drinking and driving is a global
tragedy.
Alcohol affects four things that
anyone needs to drive a vehicle:
judgment, muscular coordination,
vision, and attentiveness.
Police records show that
almost 40 percent of all motor
vehicle-related deaths involve
alcohol. In most cases, these
deaths are the result of someone
who was drinking and driving.
In recent years, more than
17,000 annual motor vehicle-related
deaths have been associated with
the use of alcohol, with about
250,000 people injured.
For persons under 21, it is against
the law in every U.S. state to drink
alcohol. There are good medical,
psychological, and developmental
reasons for these laws.
The obvious way to eliminate the
leading highway safety problem is
for people never to drink alcohol
and then drive.Medical research shows that
alcohol in a person's system
can make crash injuries worse,
especially injuries to the brain,
spinal cord, or heart. This means
that when anyone who has been
drinking
—driver or passenger —is
in a crash, that person's chance of
being killed or permanently disabled
is higher than if the person had not
been drinking.
Control of a Vehicle
The following three systems
help to control the vehicle while
driving —brakes, steering, and
accelerator. At times, as when
driving on snow or ice, it is easy to
ask more of those control systems
than the tires and road can provide.
Meaning, you can lose control of the
vehicle. See StabiliTrak
®System on
page 9‑70.
Adding non‐dealer accessories
can affect vehicle performance.
See Accessories and Modifications
on page 10‑3.
Braking
See Brake System Warning Light on
page 5‑27.
Braking action involves perception
time and reaction time. Deciding
to push the brake pedal is
perception time. Actually doing
it is reaction time.
Average reaction time is about
three‐fourths of a second. But that
is only an average. It might be less
with one driver and as long as two
or three seconds or more with
another. Age, physical condition,
alertness, coordination, and
eyesight all play a part. So do
alcohol, drugs, and frustration. But
even in three‐fourths of a second,
a vehicle moving at 100 km/h
(60 mph) travels 20 m (66 ft).
That could be a lot of distance in
an emergency, so keeping enough
space between the vehicle and
others is important.

Black plate (4,1)GMC Sierra Owner Manual - 2011
9-4 Driving and Operating
And, of course, actual stopping
distances vary greatly with the
surface of the road, whether it is
pavement or gravel; the condition
of the road, whether it is wet, dry,
or icy; tire tread; the condition of the
brakes; the weight of the vehicle;
and the amount of brake force
applied.
Avoid needless heavy
braking. Some people drive in
spurts—heavy acceleration
followed by heavy braking —rather
than keeping pace with traffic.
This is a mistake. The brakes
might not have time to cool between
hard stops. The brakes will wear
out much faster with a lot of heavy
braking. Keeping pace with the
traffic and allowing realistic following
distances eliminates a lot of
unnecessary braking. That means
better braking and longer brake life.
If the engine ever stops while the
vehicle is being driven, brake
normally but do not pump the brakes. If the brakes are pumped,
the pedal could get harder to push
down. If the engine stops, there will
still be some power brake assist but
it will be used when the brake is
applied. Once the power assist is
used up, it can take longer to stop
and the brake pedal will be harder
to push.
Adding non‐dealer accessories
can affect vehicle performance.
See
Accessories and Modifications
on page 10‑3.
Steering
Power Steering
If the vehicle is a hybrid, see
the hybrid supplement for more
information.
If power steering assist is lost
because the engine stops or the
power steering system is not
functioning, the vehicle can be
steered but it will take more effort.
Steering Tips
It is important to take curves at a
reasonable speed.
Traction in a curve depends on the
condition of the tires and the road
surface, the angle at which the
curve is banked, and vehicle speed.
While in a curve, speed is the one
factor that can be controlled.
If there is a need to reduce speed,
do it before entering the curve, while
the front wheels are straight.
Try to adjust the speed so you can
drive through the curve. Maintain a
reasonable, steady speed. Wait to
accelerate until out of the curve,
and then accelerate gently into
the straightaway.

Black plate (6,1)GMC Sierra Owner Manual - 2011
9-6 Driving and Operating
Loss of Control
Let us review what driving experts
say about what happens when the
three control systems—brakes,
steering, and acceleration —do not
have enough friction where the tires
meet the road to do what the driver
has asked.
In any emergency, do not give up.
Keep trying to steer and constantly
seek an escape route or area of
less danger.
Skidding
In a skid, a driver can lose control of
the vehicle. Defensive drivers avoid
most skids by taking reasonable
care suited to existing conditions,
and by not overdriving those
conditions. But skids are always
possible. The three types of skids correspond
to the vehicle's three control
systems. In the braking skid,
the wheels are not rolling. In the
steering or cornering skid, too much
speed or steering in a curve causes
tires to slip and lose cornering force.
And in the acceleration skid, too
much throttle causes the driving
wheels to spin.
If the vehicle starts to slide, ease
your foot off the accelerator pedal
and quickly steer the way you
want the vehicle to go. If you start
steering quickly enough, the vehicle
may straighten out. Always be ready
for a second skid if it occurs.
Of course, traction is reduced when
water, snow, ice, gravel, or other
material is on the road. For safety,
slow down and adjust your driving to
these conditions. It is important to
slow down on slippery surfaces
because stopping distance is longer
and vehicle control more limited.
While driving on a surface with
reduced traction, try to avoid
sudden steering, acceleration,
or braking, including reducing
vehicle speed by shifting to a lower
gear. Any sudden changes could
cause the tires to slide. You might
not realize the surface is slippery
until the vehicle is skidding. Learn
to recognize warning clues
—such
as enough water, ice, or packed
snow on the road to make a
mirrored surface —and slow
down when you have any doubt.
Remember: Antilock brakes help
avoid only the braking skid.

Black plate (9,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-9
WARNING (Continued)
.Heavy loads on the roof raise
the vehicle's center of gravity,
making it more likely to roll
over. You can be seriously or
fatally injured if the vehicle
rolls over. Put heavy loads
inside the cargo area, not on
the roof. Keep cargo in the
cargo area as far forward
and low as possible.
There are some important things to
remember about how to load your
vehicle.
.The heaviest things should be
on the floor, forward of the rear
axle. Put heavier items as far
forward as you can.
.Be sure the load is properly
secured, so things are not
tossed around.
You will find other important
information under Vehicle Load
Limits on page 9‑25 andTires on
page 10‑57.
Environmental Concerns
Off-road driving can provide
wholesome and satisfying
recreation. However, it also
raises environmental concerns.
We recognize these concerns
and urge every off-roader to follow
these basic rules for protecting
the environment:
.Always use established trails,
roads, and areas that have been
specially set aside for public
off-road recreational driving and
obey all posted regulations.
.Avoid any driving practice
that could damage shrubs,
flowers, trees, or grasses or
disturb wildlife. This includes
wheel-spinning, breaking down
trees, or unnecessary driving
through streams or over soft
ground.
.Always carry a litter bag and
make sure all refuse is removed
from any campsite before
leaving.
.Take extreme care with open
fires (where permitted), camp
stoves, and lanterns.
.Never park your vehicle over
dry grass or other combustible
materials that could catch fire
from the heat of the vehicle's
exhaust system.

Black plate (16,1)GMC Sierra Owner Manual - 2011
9-16 Driving and Operating
Driving Across an Incline
An off-road trail will probably go
across the incline of a hill. To decide
whether to try to drive across the
incline, consider the following:
{WARNING
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.
.A hill that can be driven straight
up or down might be too steep
to drive across. When going
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 driving
across an incline, the narrower
track width
—the distance
between the left and right
wheels —might not prevent the
vehicle from tilting and rolling
over. Driving across an incline
puts more weight on the downhill
wheels which could cause a
downhill slide or a rollover.
.Surface conditions can be a
problem. Loose gravel, muddy
spots, or even wet grass can
cause the 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, the vehicle can tilt
even more. For these reasons, carefully
consider 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.
If you feel the vehicle starting
to slide sideways, turn downhill.
This should help straighten out
the vehicle and prevent the side
slipping. The best way to prevent
this is to
“walk the course” first, so
you know what the surface is like
before driving it.

Black plate (17,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-17
Stalling on an Incline
{WARNING
Getting out on the downhill (low)
side of a vehicle stopped across
an incline is dangerous. If the
vehicle rolls over, you could be
crushed or killed. Always get out
on the uphill (high) side of the
vehicle and stay well clear of the
rollover path.
If the vehicle stalls when crossing
an incline, be sure you, and
any passengers, get out on the
uphill side, even if the door there
is harder to open. If you get out on
the downhill side and the vehicle
starts to roll over, you will be right
in its path.
If you have to walk down the slope,
stay out of the path the vehicle will
take if it does roll over.
Driving in Mud, Sand, Snow,
or Ice
When you drive in mud, snow,
or sand, the wheels do not get
good traction. Acceleration is not
as quick, turning is more difficult,
and braking distances are longer.
It is best to use a low gear when
in mud —the deeper the mud, the
lower the gear. In really deep mud,
keep the vehicle moving so it does
not get stuck.
When driving on sand, wheel
traction changes. On loosely packed
sand, such as on beaches or sand
dunes, the tires will tend to sink into
the sand. This affects 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 the vehicle does get moving,
poor steering and difficult braking
can cause it to slide out of control.
{WARNING
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.

Black plate (18,1)GMC Sierra Owner Manual - 2011
9-18 Driving and Operating
Driving in Water
{WARNING
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.
Heavy rain can mean flash flooding,
and flood waters demand extreme
caution. Find out how deep the water is
before driving through it. Do not
try it if it is deep enough to cover
the wheel hubs, axles, or exhaust
pipe
—you probably will not get
through. Deep water can damage
the axle and other vehicle parts.
If the water is not too deep, drive
slowly through it. At faster speeds,
water splashes on the ignition
system and the vehicle can stall.
Stalling can also occur if you get the
tailpipe under water. If the tailpipe is
under water, you will never be able
to start the engine. When going
through water, remember that when
the brakes get wet, it might take
longer to stop. See Driving on Wet
Roads on page 9‑19.
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 fire hazard.
After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, steering,
suspension, wheels, tires, and
exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
The vehicle requires more frequent
service due to off-road use. Refer
to the Maintenance Schedule for
additional information.

Black plate (19,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-19
Driving on Wet Roads
Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep‐standing or flowing water.
{WARNING
Wet brakes can cause crashes.
They might not work as well in
a quick stop and could cause
pulling to one side. You could
lose control of the vehicle.(Continued)
WARNING (Continued)
After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to
drive through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road
is wet enough and you are going
fast enough. When the vehicle is
hydroplaning, it has little or no
contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.