Maserati Quattroporte Automatic 2009, Owner'S Manual

Page: 183 / 276

5
Tires
183
DOT Quality Grades
(*) Example only
Treadwear
The treadwear grade is a comparative
rating based on the wear rate of the
tire when tested under controlled
conditions on a specified government
test course.
For example, a tire graded 150 would
wear one and one-half (1
1
/
2
) times as
well on the government course as a
tire graded 100.
The relative performance of tires
depends upon the actual conditions of
their use and may depart significantly
from the norm due to variations in
driving habits, service practices and
differences in road characteristics and
climate.
Traction
The traction grades, from highset to
lowest, are “AA”, “A”, “B”, and “C”.
Those 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.
The traction grade assigned to
this tire is based on straight-
ahead braking traction tests,
and does not include acceleration,
cornering, hydroplaning, or peak
traction characteristics
Tires Tread wear Traction Temperature
Michelin Pilot Sport (*) 220 AA A
Temperature
The temperature grades are "A" (the
highest), "B", and "C", representing
the tire 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 tire to
deteriorate and can reduce tire life. In
addition, 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 Safety Standard No. 109. Grades
"B" and "A" represent higher levels of
performance on the laboratory test
wheel than the minimum required by
law.
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.
M139_UM_usa1.book Page 183 Monday, September 1, 2008 2:39 PM