Lincoln 2014 MKZ Owner's Manual page 312

The traction grades, from highest
to lowest are AA, A, B, and C. The
grades represent the tire's ability
to stop on wet pavement as
measured under controlled
conditions on specified
government test surfaces of
asphalt and concrete. A tire
marked C may have poor traction
performance.
Temperature A B C
WARNING
The temperature grade for
this tire is established for a
tire that is properly inflated and
not overloaded. Excessive speed,
underinflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.
The temperature grades are A
(the highest), B and C,
representing the tire's resistance
to the generation of heat and its
ability to dissipate heat when
tested under controlled conditions
on a specified indoor laboratory
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
Wheels and Tires
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
•
•
•
•
•
•
309
Tire label: A label showing the
original equipment tire sizes,
recommended inflation
pressure and the maximum
weight the vehicle can carry.
Tire Identification Number:
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.