Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16401961) - 2023 - CRC - 5/17/22
280 Vehicle Care
(1) Tire Ply Material:The type of cord
and number of plies in the sidewall and
under the tread.
(2) Temporary Use Only
:The compact
spare tire or temporary use tire should
not be driven at speeds over 80 km/h
(50 mph). The compact spare tire is for
emergency use when a regular road tire
has lost air and gone flat. If the vehicle
has a compact spare tire, see Compact
Spare Tire 0301 and
If a Tire Goes Flat 0295.
(3) Tire Identification Number (TIN)
:
The letters and numbers following the
DOT (Department of Transportation)
code are the Tire Identification 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.
(4) Maximum Cold Inflation Load
Limit
:Maximum load that can be
carried and the maximum pressure
needed to support that load. (5) Tire Inflation
:The temporary use
tire or compact spare tire should be
inflated to 420 kPa (60 psi). For more
information on tire pressure and
inflation see Tire Pressure 0283.
(6) Tire Size
:A combination of letters
and numbers define a tire's width,
height, aspect ratio, construction type,
and service description. The letter “T”as
the first character in the tire size means
the tire is for temporary use only.
(7) TPC Spec (Tire Performance Criteria
Specification)
:Original equipment tires
designed to GM's specific tire
performance criteria have a TPC
specification code molded onto the
sidewall. GM's TPC specifications meet
or exceed all federal safety guidelines.
Tire Designations
Tire Size
The example shows a typical passenger
vehicle tire size.
Passenger (P-Metric) Tire
(1) Passenger (P-Metric) Tire:The
United States version of a metric tire
sizing system. The letter "P" as the first
character in the tire size means a
passenger vehicle tire engineered to
standards set by the U.S. Tire and Rim
Association.
(2) Tire Width
:The 3-digit number
indicates the tire section width in
millimeters from sidewall to sidewall.
(3) Aspect Ratio
:A 2-digit number that
indicates the tire height-to-width
measurements. For example, if the tire
size aspect ratio is 75, as shown in
item (3) of the illustration, it would
mean that the tire's sidewall is
75 percent as high as it is wide.
Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16401961) - 2023 - CRC - 5/17/22
Vehicle Care 281
(4) 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.
(5) Rim Diameter
:Diameter of the
wheel in inches.
(6) Service Description
:These
characters represent the load index and
speed rating of the tire. The load index
represents the load carrying capacity a
tire is certified to carry. The speed
rating is the maximum speed a tire is
certified to carry a load.
Tire Terminology and Definitions
Air Pressure:The amount of air inside
the tire pressing outward on each
square inch of the tire. Air pressure is
expressed in kPa (kilopascal) or psi
(pounds per square inch).
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 kPa
(kilopascal) or psi (pounds per square
inch) before a tire has built up heat
from driving. See Tire Pressure0283.
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 Identification
Number (TIN), an alphanumeric
designator which can also identify the
tire manufacturer, production plant,
brand, and date of production. GVWR
:Gross Vehicle Weight Rating.
See Vehicle Load Limits 0188.
GAWR FRT
:Gross Axle Weight Rating
for the front axle. See Vehicle Load
Limits 0188.
GAWR RR
:Gross Axle Weight Rating
for the rear axle. See Vehicle Load
Limits 0188.
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 Inflation Pressure
:The
maximum air pressure to which a cold
tire can be inflated. The maximum air
pressure is molded onto the sidewall.
Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16401961) - 2023 - CRC - 5/17/22
294 Vehicle Care
such as troughs or ruts, is normal. If the
vehicle is vibrating when driving on a
smooth road, the tires and wheels may
need to be rebalanced. See your dealer for
proper diagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked,
or badly rusted or corroded. If wheel nuts
keep coming loose, the wheel, wheel bolts,
and wheel nuts should be replaced. If the
wheel leaks air, replace it. Some aluminum
wheels can be repaired. See your dealer if
any of these conditions exist.
Your dealer will know the kind of wheel that
is needed.
Each new wheel should have the same
load-carrying capacity, diameter, width,
offset, and be mounted the same way as
the one it replaces.
Replace wheels, wheel bolts, wheel nuts,
or Tire Pressure Monitor System (TPMS)
sensors with new GM original equipment
parts.
{Warning
Using the wrong replacement wheels,
wheel bolts, or wheel nuts can be
dangerous. It could affect the braking and
handling of the vehicle. Tires can lose air
and cause loss of control, resulting in a
crash. Always use the correct wheel,
wheel bolts, and wheel nuts for
replacement.
{Warning
Replacing a wheel with a used one is
dangerous. How it has been used or how
far it has been driven may be unknown.
It could fail suddenly and cause a crash.
When replacing wheels, use a new GM
original equipment wheel.
Caution
The wrong wheel can also cause
problems with bearing life, brake cooling,
speedometer or odometer calibration,
headlamp aim, bumper height, vehicle
ground clearance, and tire or tire chain
clearance to the body and chassis.
Tire Chains
{Warning
If the vehicle has 235/55R20 or 265/45R21
size tires, do not use tire chains. 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 loss of control and a crash.
Use another type of traction device only
if its manufacturer recommends it for the
vehicle's tire size combination and road
conditions. Follow that manufacturer's
instructions. To avoid vehicle damage,
drive slow and readjust or remove the
traction device if it contacts the vehicle.
Do not spin the wheels. If traction
devices are used, install them on the tires
of the drive axle only.
Caution
If the vehicle is equipped with a tire size
other than 235/55R20 or 265/45R21 use
tire chains only where legal and only
(Continued)
