(A) Temporary Use Only:The compact spare
tire or temporary use tire has a tread life of
approximately 3,000 miles (5 000 km) and should
not be driven at speeds over 65 mph (105 km/h).
The compact spare tire is for emergency use
when a regular road tire has lost air and gone at.
See “Compact Spare Tire” underSpare Tire
on page 5-98for additional information.(B) Tire Ply Material
:The type of cord and
number of plies in the sidewall and under the tread.
(C) Tire Identi cation Number (TIN)
:The Tire
Identi cation 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.
(D) Maximum Cold In ation Load Limit
:Maximum load that can be carried and the
maximum pressure needed to support that load.
(E) Tire In ation
:The temporary use tire
or compact spare tire should be in ated to
60 psi (420 kPa). For more information on tire
pressure and in ation seeInflation - Tire
Pressure on page 5-62.
(F) Tire Size
:A combination of letters and
numbers de ne a tire’s width, height, aspect
ratio, construction type and service description.
The letter T as the rst character in the tire
size means the tire is for temporary use only.
(G) TPC Spec (Tire Performance Criteria
Speci cation)
:Original equipment tires designed
to GM’s speci c tire performance criteria have
a TPC speci cation code molded onto the sidewall.
GM’s TPC speci cations meet or exceed all
federal safety guidelines.
Compact Spare Tire Example
5-58
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. SeeInflation - Tire Pressure
on page 5-62.
Curb Weight
: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 Identi cation 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
Loading Your Vehicle on page 4-32.
GAWR FRT
:Gross Axle Weight Rating for the
front axle. SeeLoading Your Vehicle on page 4-32.
GAWR RR
:Gross Axle Weight Rating for the rear
axle. SeeLoading Your Vehicle on page 4-32.
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 In ation Pressure
:The maximum air
pressure to which a cold tire can be in ated. The
maximum air pressure is molded onto the sidewall.
Maximum Load Rating
:The load rating for a tire
at the maximum permissible in ation pressure
for that tire.
5-60
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 4-32.
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 In ation Pressure
:Vehicle
manufacturer’s recommended tire in ation
pressure as shown on the tire placard.
SeeInflation - Tire Pressure on page 5-62
andLoading Your Vehicle on page 4-32.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 5-71.
5-61
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 5-74.
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 4-32.
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 in ation pressure. See “Tire and
Loading Information Label” underLoading
Your Vehicle on page 4-32.
In ation - Tire Pressure
Tires need the correct amount of air pressure
to operate effectively.
Notice:Do not let anyone tell you that
under-in ation or over-in ation is all right.
It is not. If your tires do not have enough air
(under-in ation), 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-in ation),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazards
5-62