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 Inflation Pressure: Vehicle
manufacturer’s recommended tire inflation
pressure as shown on the tire placard. See
Inflation - Tire Pressure on page 392 and Loading
Your Vehicle on page 307.
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. See When It Is Time for New Tires on
page 400.
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. See Uniform
Tire Quality Grading on page 402.
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