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 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 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.
•
bar
Metric unit of atmospheric
pressure.
•
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 mi (1.6 km).
•
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 seating position) or Tire
Label located on the B-Pillar or
the edge of the driver 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.
244
Transit (TTH) Canada/United States of America, enUSA, First Printing
Wheels and Tires
