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
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 set
pressure. For example: for
P-metric tires 35 psi (2.4 bar) or
36 psi (2.5 bar) depending on tire
size and for Metric tires 36 psi
(2.5 bar). 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 42 psi
(2.9 bar). 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.
*
Tread area of the tire:
Area of
the perimeter of the tire that
contacts the road when mounted
on the vehicle.
*
Rim:
The metal support (wheel)
for a tire or a tire and tube
assembly upon which the tire
beads are seated.
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C-MAX (CCG) Canada/United States of America, enUSA, First Printing
Wheels and Tires
