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 5-67.
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 5-70.
Vehicle Capacity Weight
: The number of
designated seating positions multiplied by 150 lbs
(68 kg) plus the rated cargo load. See Loading
the Vehicle on page 4-20.
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 the
Vehicle on page 4-20.
5-58