Page 501 of 594

Black plate (77,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-77
Vehicle Storage
Tires age when stored normally
mounted on a parked vehicle. Park
a vehicle that will be stored for at
least a month in a cool, dry, clean
area away from direct sunlight to
slow aging. This area should be
free of grease, gasoline or other
substances that can deteriorate
rubber.
Parking for an extended period
can cause flat spots on the tires
that may result in vibrations while
driving. When storing a vehicle for
at least a month, remove the tires
or raise the vehicle to reduce the
weight from the tires.
Buying New Tires
GM has developed and matched
specific tires for the vehicle.
The original equipment tires
installed on the vehicle, when
it was new, were designed to meet
General Motors Tire Performance
Criteria Specification (TPC Spec)
system rating. If you need
replacement tires, GM strongly
recommends that you get tires
with the same TPC Spec rating.
This way, the vehicle will continue
to have tires that are designed to
give the same performance and
vehicle safety, during normal use,
as the original tires.GM's exclusive TPC Spec system
considers over a dozen critical
specifications that impact the
overall performance of the
vehicle, including brake system
performance, ride and handling,
traction control, and tire pressure
monitoring performance. GM's TPC
Spec number is molded onto the
tire's sidewall near the tire size.
If the tires have an all‐season
tread design, the TPC spec
number will be followed by an
MS for mud and snow. See
Tire
Sidewall Labeling on page 10‑58
for additional information.
Page 503 of 594

Black plate (79,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-79
Vehicles that have a tire pressure
monitoring system may give an
inaccurate low‐pressure warning
if non‐TPC Spec-rated tires are
installed on the vehicle. Non‐TPC
Spec-rated tires may give a
low‐pressure warning that is
higher or lower than the proper
warning level you would get with
TPC Spec-rated tires. SeeTire
Pressure Monitor System on
page 10‑68.
The vehicle's original equipment
tires are listed on the Tire and
Loading Information label. See
Vehicle Load Limits on page 9‑25
for more information about the Tire
and Loading Information label and
its location on the vehicle.Different Size Tires and
Wheels
If you add wheels or tires that are
a different size than the original
equipment wheels and tires, this
could affect the way the vehicle
performs, including its braking,
ride and handling characteristics,
stability, and resistance to rollover.
Additionally, if the vehicle has
electronic systems such as antilock
brakes, rollover airbags, traction
control, and electronic stability
control, the performance of these
systems can be affected.
{WARNING
If different sized wheels are used,
there may not be an acceptable
level of performance and safety
if tires not recommended for
those wheels are selected.
This increases the chance
of a crash and serious injury.
Only use GM specific wheel
and tire systems developed
for the vehicle, and have them
properly installed by a GM
certified technician.
See Buying New Tires on
page 10‑77 andAccessories
and Modifications on page 10‑3
for additional information.
Page 504 of 594

Black plate (80,1)GMC Sierra Owner Manual - 2011
10-80 Vehicle Care
Uniform Tire Quality
Grading
Quality grades can be found
where applicable on the tire
sidewall between tread shoulder
and maximum section width.
For example:
Treadwear 200 Traction AA
Temperature A
The following information relates
to the system developed by the
United States National Highway
Traffic Safety Administration
(NHTSA), which grades tires
by treadwear, traction, and
temperature performance.
This applies only to vehicles
sold in the United States.
The grades are molded on the
sidewalls of most passenger car
tires. The Uniform Tire QualityGrading (UTQG) system
does not apply to deep
tread, winter-type snow tires,
space-saver, or temporary use
spare tires, tires with nominal
rim diameters of 10 to 12 inches
(25 to 30 cm), or to some
limited-production tires.
While the tires available on
General Motors passenger
cars and light trucks may vary
with respect to these grades,
they must also conform to
federal safety requirements and
additional General Motors Tire
Performance Criteria (TPC)
standards.
All Passenger Car Tires Must
Conform to Federal Safety
Requirements In Addition To
These Grades.
Treadwear
The treadwear grade is a
comparative rating based
on the wear rate of the tire
when tested under controlled
conditions on a specified
government test course.
For example, a tire graded
150 would wear one and a
half (1½) times as well on
the government course as
a tire graded 100. The relative
performance of tires depends
upon the actual conditions of
their use, however, and may
depart significantly from the
norm due to variations in
driving habits, service practices
and differences in road
characteristics and climate.
Page 505 of 594

Black plate (81,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-81
Traction–AA, A, B, C
The traction grades, from
highest to lowest, are AA, A, B,
and C. Those grades represent
the tire's ability to stop on
wet pavement as measured
under controlled conditions
on specified government
test surfaces of asphalt and
concrete. A tire marked C may
have poor traction performance.
Warning: The traction grade
assigned to this tire is based
on straight-ahead braking
traction tests, and does not
include acceleration, cornering,
hydroplaning, or peak traction
characteristics.
Temperature –A, B, C
The temperature grades
are A (the highest), B, and C,
representing the tire's resistance
to the generation of heat and its
ability to dissipate heat when tested under controlled
conditions on a specified
indoor laboratory test wheel.
Sustained high temperature can
cause the material of the tire to
degenerate and reduce tire life,
and excessive temperature
can lead to sudden tire failure.
The grade C corresponds to a
level of performance which all
passenger car tires must meet
under the Federal Motor Safety
Standard No. 109. Grades B
and A represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law. Warning: The
temperature grade for this tire
is established for a tire that
is properly inflated and not
overloaded. Excessive speed,
underinflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.Wheel Alignment and Tire
Balance
The tires and wheels on the vehicle
were aligned and balanced carefully
at the factory to give the longest tire
life and best overall performance.
Adjustments to wheel alignment and
tire balancing will not be necessary
on a regular basis. However, if there
is unusual tire wear or the vehicle
pulls to one side or the other, the
alignment should be checked. If the
vehicle vibrates when driving on a
smooth road, the tires and wheels
might need to be rebalanced. See
your dealer for proper diagnosis.
Page 507 of 594

Black plate (83,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-83
Tire Chains
{WARNING
If the vehicle has dual wheels
or P265/65R18, P275/55R20,
LT265/70R17, LT265/70R18,
LT265/60R20, P285/50R20,
P285/45R22 or 285/45R22 size
tires, do not use tire chains.
They can damage the vehicle
because there is not enough
clearance. Tire chains used on
a vehicle without the proper
amount of clearance can
cause damage to the brakes,
suspension, or other vehicle
parts. The area damaged by the
tire chains could cause you to
lose control of the vehicle and
you or others may be injured in
a crash.(Continued)
WARNING (Continued)
Use another type of traction
device only if its manufacturer
recommends it for use on the
vehicle and tire size combination
and road conditions. Follow
that manufacturer's instructions.
To help avoid damage to the
vehicle, drive slowly, readjust,
or remove the device if it is
contacting the vehicle, and do
not spin the vehicle's wheels.
If you do find traction devices that
will fit, install them on the rear
tires. Notice:
If the vehicle does not
have dual wheels and has a
tire size other than P265/65R18,
P275/55R20, LT265/70R17, LT265/
70R18, LT265/60R20, P285/50R20,
P285/45R22, or 285/45R22, use
tire chains only where legal and
only when you must. Use chains
that are the proper size for the
tires. Install them on the tires
of the rear axle. Do not use
chains on the tires of the front
axle. Tighten them as tightly as
possible with the ends securely
fastened. Drive slowly and
follow the chain manufacturer's
instructions. If you can hear the
chains contacting the vehicle,
stop and retighten them. If the
contact continues, slow down
until it stops. Driving too fast or
spinning the wheels with chains
on will damage the vehicle.