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Speed rating (letter code)
means the speed at wh ich a tire is designed to
be driven for extended periods of t ime . The
ratings range from 93 mph (150 km/h) to
186 mph (298 km/h) ¢
page 247 .
You may
not find this information on all tires because
it is not required by law.
The speed rating letter code, where applica-
ble, is molded on the tire sidewall and indi-
cates the maximum permissible road speeds
¢ &. in Winter tires on page 250.
Tire pressure monitoring system*
means a system that detects when one or
more of a vehicle's tires are underinflated and
illuminates a low tire pressure warn ing te ll -
tale .
Tread
means that port ion of a tire that comes into
contact with the road.
Tread separation
means pulling away of the tread from the tire
carcass.
Treadwear indicators (TWI)
means the projections within the pr incipal
grooves designed to give a visual ind ication of
the degrees of wear of the tread . See
¢
page 244, Tread Wear Indicator (TWI)
for
mo re inf ormat ion on measuring tire wear.
Uniform Tire Quality Grading
is a tire information system developed by the
United States National Highway Traffic Safety
Admin istration (NHTSA) that is designed to
help buyers make relative compa risons among
tires . The UTQG is not a safety rating and not a
guarant ee that a t ire will last for a prescribed
number of mi les (kilometers) or perform in a
certain way. It simply gives tire buyers addi -
tional information to combine with other con-
Tires and wheels
237
siderations, such as price, brand loyalty and
dealer recommendations. Under UTQG, tires
are graded by the t ire manufacturers in three
areas: treadwear, traction, and temperature
resistance. The UTQG informat ion on the tires,
molded into the sidewalls .
U.S. DOT Tire Identification Number (TIN)
This is the tire's "serial number" . It begins
with the letters "DOT" and indicates that the
tire meets all federa l standards. The next two
numbers or letters ind icate the plant where it
was manufactured, and the last four numbers
represent the week and year of manufacture.
For example,
DOT ... 2212 ...
means that the tire was produced in the 22nd
week of 2012. The other numbers are market-
ing codes that may or may not be used by the
tire manufacturer. This information is used to
contact consumers if a tire defect requires a
recall.
Vehicle capacity weight
means the rated cargo and luggage load plus
150 lbs. (68 kilograms) times the vehicle's to-
tal seating capacity as listed on the label lo-
cated on the driver's side B-pillar .
Vehicle maximum load on the tire
means that load on an individual tire that is
determined by distributing to each axle its
share of the maximum loaded vehicle weight
and dividing by two.
Vehicle normal load on the tire
means that load on an individual tire that is
determined by distributing to each axle its
share of the curb weight, accessory weight,
and normal occupant weight (distr ibuted in
accordance with table below ¢
page 238)
and dividing by two.
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