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 2/32 inch of tread remains. See When 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.
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 5-71.
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 4-33.
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 original equipment tire size and
recommended inflation pressure. See Loading
Your Vehicle on page 4-33.
5-65