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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 4-31.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. See
Inflation - Tire Pressure on page 5-60andLoading
the Vehicle on page 4-31.
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.
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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 5-69.
UTQGS (Uniform Tire Quality Grading
Standards)
:A tire information system that
provides consumers with ratings for a tire’s
traction, temperature, and treadwear. Ratingsare determined by tire manufacturers using
government testing procedures. The ratings are
molded into the sidewall of the tire. SeeUniform
Tire Quality Grading on page 5-72.
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 4-31.
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 4-31.
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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 4-31. 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 the vehicle has one. SeeSpare Tire on
page 5-102for additional information.
How to Check
Use a good quality pocket-type gage to check tire
pressure. You cannot tell if your tires are properly
in ated simply by looking at them. Radial tires
may look properly in ated even when they areunderin ated. Check the tire’s in ation 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
in ation 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 over ll 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.
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