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 and
shown on the tire placard. See Inflation - Tire Pressure
on page 5-66 and Loading 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. See
When It Is Time for New Tires on page 5-73.
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 5-76.
Vehicle Capacity Weight: The number of designated
seating positions multiplied by 150 lbs (68 kg) plus
the rated cargo load. See Loading 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
inflation pressure. See “Tire and Loading Information
Label” under Loading Your Vehicle on page 4-32.
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