CHEVROLET TRAIL BLAZER 2007 1.G Owners Manual

(E) Tire Ply Material:The type of cord and number
of plies in the sidewall and under the tread.
(F) Uniform Tire Quality Grading (UTQG):
Tire manufacturers are required to grade
tires based on three performance factors:
treadwear, traction, and temperature resistance.
For more information, seeUniform Tire Quality
Grading on page 469.
(G) Maximum Cold Ination Load Limit:
Maximum load that can be carried and the
maximum pressure needed to support that load.
For information on recommended tire pressure
seeInation - Tire Pressure on page 457
andLoading Your Vehicle on page 356.
(A) Tire Size:The tire size code is a combination
of letters and numbers used to dene a particular
tire’s width, height, aspect ratio, construction
type, and service description. See the “Tire Size”
illustration later in this section for more detail.
Light Truck (LT-Metric) Tire
451

(B) TPC Spec (Tire Performance Criteria
Specication):Original equipment tires designed
to GM’s specic tire performance criteria have
a TPC specication code molded onto the sidewall.
GM’s TPC specications meet or exceed all
federal safety guidelines.
(C) Dual Tire Maximum Load:Maximum load
that can be carried and the maximum pressure
needed to support that load when used in a dual
conguration. For information on recommended
tire pressure seeInation - Tire Pressure on
page 457andLoading Your Vehicle on page 356.
(D) DOT (Department of Transportation):
The Department of Transportation (DOT) code
indicates that the tire is in compliance with the
U.S. Department of Transportation Motor Vehicle
Safety Standards.(E) Tire Identication Number (TIN):The letters
and numbers following DOT code are the Tire
Identication Number (TIN). The TIN shows
the manufacturer and plant code, tire size, and
date the tire was manufactured. The TIN is molded
onto both sides of the tire, although only one side
may have the date of manufacture.
(F) Tire Ply Material:The type of cord and number
of plies in the sidewall and under the tread.
(G) Single Tire Maximum Load:Maximum load
that can be carried and the maximum pressure
needed to support that load when used as a
single. For information on recommended
tire pressure seeInation - Tire Pressure on
page 457andLoading Your Vehicle on page 356.
452

Tire Size
The following examples show the different parts of
a tire size.
(A) Passenger (P-Metric) Tire:The United
States version of a metric tire sizing system.
The letter P as the rst character in the tire size
means a passenger vehicle tire engineered
to standards set by the U.S. Tire and Rim
Association.(A) Light Truck (LT-Metric) Tire:The United
States version of a metric tire sizing system.
The letters LT as the rst two characters in the
tire size means a light truck tire engineered
to standards set by the U.S. Tire and Rim
Association.
(B) Tire Width:The three-digit number indicates
the tire section width in millimeters from sidewall
to sidewall.
(C) Aspect Ratio:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 75,
as shown in item C of the light truck (LT-Metric) tire
illustration, it would mean that the tire’s sidewall is
75 percent as high as it is wide.
(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire.
The letter R means radial ply construction; the
letter D means diagonal or bias ply construction;
and the letter B means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a
tire. The load index can range from 1 to 279.
Speed ratings range from A to Z.
Passenger (P-Metric) Tire
Light Truck (LT-Metric) Tire
453

Tire Terminology and Denitions
Air Pressure:The amount of air inside the tire
pressing outward on each square inch of the
tire. Air pressure is expressed in pounds
per square inch (psi) or kilopascal (kPa).
Accessory Weight:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic transmission,
power steering, power brakes, power windows,
power seats, and air conditioning.
Aspect Ratio:The relationship of a tire’s height
to its width.
Belt:A rubber coated layer of cords that is
located between the plies and the tread. Cords
may be made from steel or other reinforcing
materials.
Bead:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.
Bias Ply Tire:A pneumatic tire in which the plies
are laid at alternate angles less than 90 degrees
to the centerline of the tread.Cold Tire Pressure:The amount of air pressure
in a tire, measured in pounds per square
inch (psi) or kilopascals (kPa) before a tire has
built up heat from driving. SeeInation - Tire
Pressure on page 457.
Curb Weight:This means the weight of a motor
vehicle with standard and optional equipment
including the maximum capacity of fuel, oil, and
coolant, but without passengers and cargo.
DOT Markings:A code molded into the sidewall
of a tire signifying that the tire is in compliance
with the U.S. Department of Transportation (DOT)
motor vehicle safety standards. The DOT code
includes the Tire Identication Number (TIN),
an alphanumeric designator which can also identify
the tire manufacturer, production plant, brand,
and date of production.
GVWR:Gross Vehicle Weight Rating.
SeeLoading Your Vehicle on page 356.
GAWR FRT:Gross Axle Weight Rating for the
front axle. SeeLoading Your Vehicle on page 356.
GAWR RR:Gross Axle Weight Rating for the
rear axle. SeeLoading Your Vehicle on page 356.
454

Intended Outboard Sidewall:The side of an
asymmetrical tire, that must always face outward
when mounted on a vehicle.
Kilopascal (kPa):The metric unit for air pressure.
Light Truck (LT-Metric) Tire:A tire used on
light duty trucks and some multipurpose passenger
vehicles.
Load Index:An assigned number ranging from
1 to 279 that corresponds to the load carrying
capacity of a tire.
Maximum Ination Pressure:The maximum
air pressure to which a cold tire may be inated.
The maximum air pressure is molded onto the
sidewall.
Maximum Load Rating:The load rating for a tire
at the maximum permissible ination pressure
for that tire.
Maximum Loaded Vehicle Weight:The sum of
curb weight, accessory weight, vehicle capacity
weight, and production options weight.Normal Occupant Weight:The number of
occupants a vehicle is designed to seat multiplied
by 150 lbs (68 kg). SeeLoading Your Vehicle
on page 356.
Occupant Distribution:Designated seating
positions.
Outward Facing Sidewall:The side of an
asymmetrical tire that has a particular side that
faces outward when mounted on a vehicle.
The side of the tire that contains a whitewall,
bears white lettering, or bears manufacturer,
brand, and/or model name molding that is higher
or deeper than the same moldings on the
other sidewall of the tire.
Passenger (P-Metric) Tire:A tire used on
passenger cars and some light duty trucks and
multipurpose vehicles.
Recommended Ination Pressure:Vehicle
manufacturer’s recommended tire ination
pressure as shown on the tire placard.
SeeInation - Tire Pressure on page 457and
Loading Your Vehicle on page 356.
455

Radial Ply Tire:A pneumatic tire in which the
ply cords that extend to the beads are laid at
90 degrees to the centerline of the tread.
Rim:A metal support for a tire and upon which
the tire beads are seated.
Sidewall:The portion of a tire between the tread
and the bead.
Speed Rating:An alphanumeric code assigned
to a tire indicating the maximum speed at
which a tire can operate.
Traction:The friction between the tire and the
road surface. The amount of grip provided.
Tread:The portion of a tire that comes into
contact with the road.
Treadwear Indicators:Narrow bands, sometimes
called wear bars, that show across the tread of
a tire when only 1/16 inch (1.6 mm) of tread
remains. SeeWhen It Is Time for New Tires
on page 466.UTQGS (Uniform Tire Quality Grading
Standards):A tire information system that
provides consumers with ratings for a tire’s
traction, temperature, and treadwear. Ratings are
determined by tire manufacturers using
government testing procedures. The ratings are
molded into the sidewall of the tire. SeeUniform
Tire Quality Grading on page 469.
Vehicle Capacity Weight:The number of
designated seating positions multiplied by
150 lbs (68 kg) plus the rated cargo load.
SeeLoading Your Vehicle on page 356.
Vehicle Maximum Load on the Tire:Load on
an individual tire due to curb weight, accessory
weight, occupant weight, and cargo weight.
Vehicle Placard:A label permanently attached
to a vehicle showing the vehicle’s capacity
weight and the original equipment tire size and
recommended ination pressure. See “Tire
and Loading Information Label” underLoading
Your Vehicle on page 356.
456

Ination - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-ination or over-ination is all right.
It is not. If your tires do not have enough air
(under-ination), you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air (over-ination),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazardsA Tire and Loading Information label is attached to
the vehicle’s center pillar (B-pillar), below the
driver’s door latch. This label shows your vehicle’s
original equipment tires and the correct ination
pressures for your tires when they are cold.
The recommended cold tire ination pressure,
shown on the label, is the minimum amount of air
pressure needed to support your vehicle’s
maximum load carrying capacity.
For additional information regarding how much
weight your vehicle can carry, and an example of
the tire and loading information label, see
Loading Your Vehicle on page 356. How you load
your vehicle affects vehicle handling and ride
comfort, never load your vehicle with more weight
than it was designed to carry.
When to Check
Check your tires once a month or more.
Also, check the tire pressure of the spare tire.
457

How to Check
Use a good quality pocket-type gage to check
tire pressure. You cannot tell if your tires are
properly inated simply by looking at them.
Radial tires may look properly inated even when
they’re underinated. Check the tire’s ination
pressure when the tires are cold. Cold means your
vehicle has been sitting for at least three hours
or driven no more than 1 mile (1.6 km).
Remove the valve cap from the tire valve stem.
Press the tire gage rmly onto the valve to
get a pressure measurement. If the cold tire
ination pressure matches the recommended
pressure on the tire and loading information label,
no further adjustment is necessary. If the
pressure is low, add air until you reach the
recommended amount.
If you overll the tire, release air by pushing on
the metal stem in the center of the tire valve.
Recheck the tire pressure with the tire gage.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out dirt
and moisture.
High-Speed Operation
{CAUTION:
Driving at high speeds, 100 mph (160 km/h)
or higher, puts an additional strain on tires.
Sustained high-speed driving causes
excessive heat build up and can cause
sudden tire failure. You could have a
crash and you or others could be killed.
Some high-speed rated tires require
ination pressure adjustment for high
speed operation. When speed limits and
road conditions are such that a vehicle can
be driven at high speeds, make sure the
tires are rated for high speed operation,
in excellent condition, and set to the
correct cold tire ination pressure for the
vehicle load.
458

If your vehicle has P255/50R20 104V size tires
installed on the rear axle, they will require
ination pressure adjustment when driving your
vehicle at speeds above 99 mph (160 km/h).
Set the cold ination pressure, for the rear tires
only, to the maximum ination pressure shown on
the tire sidewall, or 38 psi (262 kPa), whichever
is lower. See the example following. When you end
this high-speed driving, return the tires to the
cold tire ination pressure shown on the Tire and
Loading Information label. SeeLoading Your
Vehicle on page 356.
Example:
You will nd the maximum load and ination
pressure molded on the tire’s sidewall, in small
letters, near the rim ange. It will read something
like this: Maximum load 690 kg (1521 lbs)
300 kPa (44 psi) Max. Press.
For this example, you would set the
ination pressure for high-speed driving at
38 psi (262 kPa).The ination pressure for the front tires should be
set to the cold tire ination pressure shown on
the Tire and Loading Information label.
Racing or other competitive driving may affect the
warranty coverage of your vehicle. See your
warranty booklet for more information.
Tire Pressure Monitor System
The Tire Pressure Monitor System (TPMS) uses
radio and sensor technology to check tire pressure
levels. TPMS sensors are mounted on each tire
and wheel assembly, except the spare tire.
The TPMS sensors monitor the air pressure in
your vehicle’s tires and transmit tire pressure
readings to a receiver located in the vehicle.
The TPMS is designed to alert the driver if a low
tire pressure condition exists. If your vehicle
has the Driver Information Center (DIC) steering
wheel control buttons, tire pressure levels
may also be checked through the DIC. See “Tire
Pressures” underDIC Operation and Displays
on page 221.
459

When a low tire pressure condition is detected,
the TPMS will illuminate the low tire pressure
warning symbol located on the instrument panel
cluster, and at the same time a message will also
appear on the DIC display. The low tire pressure
warning symbol on the instrument panel cluster
and the CHECK TIRE PRESSURE warning
message on the DIC will appear at each ignition
cycle until the tires are inated to the correct
ination pressure. For additional information and
details about the DIC operation and displays
seeDIC Operation and Displays on page 221and
DIC Warnings and Messages on page 224.
You may notice, during cooler weather conditions,
that the tire pressure monitor light, located on
the instrument panel cluster, and the CHECK TIRE
PRESSURE message will appear when the
vehicle is rst started, and then turn off as you
start to drive the vehicle. This could be an
early indicator that the tire pressures are getting
low and need to be inated to the proper pressure.
Each tire, including the spare (if provided),
should be checked monthly when cold and
inated to the ination pressure recommended
by the vehicle manufacturer on the vehicle
placard or tire ination pressure label.(If your vehicle has tires of a different size than
the size indicated on the vehicle placard or tire
ination pressure label, you should determine the
proper tire ination pressure for those tires.)
As an added safety
feature, your vehicle
has been equipped
with a tire pressure
monitoring system
(TPMS) that illuminates
a low tire pressure
telltale when one
or more of your tires
is signicantly
under-inated.
Accordingly, when the low tire pressure telltale
illuminates, you should stop and check your tires
as soon as possible, and inate them to the
proper pressure. Driving on a signicantly
under-inated tire causes the tire to overheat and
can lead to tire failure. Under-ination also
reduces fuel efficiency and tire tread life, and may
affect the vehicle’s handling and stopping ability.
460