test wheel. Sustained high
temperature can cause the
material of the tire to degenerate
and reduce tire life, and excessive
temperature can lead to sudden
tire failure. The grade C
corresponds to a level of
performance which all passenger
car tires must meet under the
Federal Motor Vehicle Safety
Standard No. 139. Grades B and A
represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law.
Glossary of Tire Terminology
*
Tire label:
A label showing the
OE (Original Equipment) tire sizes,
recommended inflation pressure
and the maximum weight the
vehicle can carry.
*
Tire Identification Number
(TIN):
A number on the sidewall
of each tire providing information
about the tire brand and
manufacturing plant, tire size and
date of manufacture. Also referred
to as DOT code.
*
Inflation pressure:
A measure
of the amount of air in a tire.
*
Standard load:
A class of
P-metric or Metric tires designed
to carry a maximum load at 35 psi
[37 psi (2.5 bar) for Metric tires].
Increasing the inflation pressure
beyond this pressure will not
increase the tire’s load carrying
capability.
*
Extra load:
A class of P-metric
or Metric tires designed to carry a
heavier maximum load at 41 psi
[43 psi (2.9 bar) for Metric tires].
Increasing the inflation pressure
beyond this pressure will not
increase the tire’s load carrying
capability.
*
kPa:
Kilopascal, a metric unit of
air pressure.
*
PSI:
Pounds per square inch, a
standard unit of air pressure.
*
Cold tire pressure:
The tire
pressure when the vehicle has
been stationary and out of direct
sunlight for an hour or more and
prior to the vehicle being driven for
1 mile (1.6 kilometers).
*
Recommended inflation
pressure:
The cold inflation
pressure found on the Safety
Compliance Certification Label
(affixed to either the door hinge
pillar, door-latch post, or the door
edge that meets the door-latch
post, next to the driver's seating
position), or Tire Label located on
the B-Pillar or the edge of the
driver’s door.
*
B-pillar:
The structural member
at the side of the vehicle behind
the front door
*
Bead area of the tire:
Area of
the tire next to the rim.
*
Sidewall of the tire:
Area
between the bead area and the
tread.
219
Fiesta (CCT), enUSA, Second Printing
Wheels and Tires
