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 5-77.
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 5-81.
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 4-33.
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 4-33.
5-69