Cadillac 2005 XLR Owner's Manual page 359

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 6-58.
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 6-59.
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 5-30.
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 5-30.
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