GMC SIERRA 2009 Owner's Manual
Page 481 of 596
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 5-73.
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.
SeeLoading the Vehicle on page 4-32.
GAWR FRT
:Gross Axle Weight Rating for the
front axle. SeeLoading the Vehicle on page 4-32.
GAWR RR
:Gross Axle Weight Rating for the
rear axle. SeeLoading the 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.
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 the Vehicle on
page 4-32.
Occupant Distribution
:Designated seating
positions.
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Page 482 of 596
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. See
Inflation - Tire Pressure on page 5-73andLoading
the 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 5-83.
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 5-86.
Vehicle Capacity Weight
:The number of
designated seating positions multiplied by 150 lbs
(68 kg) plus the rated cargo load. SeeLoading
the Vehicle on page 4-32.
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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 the
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 economyIf 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
A vehicle speci c Tire and Loading Information
label is attached to your vehicle. This label shows
your vehicle’s original equipment tires and the
correct in ation pressures for your tires when they
are cold. The recommended cold tire in ation
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, seeLoading
the Vehicle on page 4-32. 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.
Do not forget to check the pressure of the spare
tire, if your vehicle has one. SeeSpare Tire
on page 5-113for additional information.
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