Maserati QUATTROPORTE Owner's Manual page 217

Tires
Driving over rough or damaged road
surfaces, as well as debris, curbs and
other obstacles can cause serious
damage to wheels, tires, and
suspension parts.
This is more likely to occur with
low-profile tires, which provide less
cushioning between the wheel and
the road.
Be careful to avoid road hazards and
reduce your speed, especially if your
vehicle is equipped with low profile
tires.
WARNING!
Overloading of your tires is
dangerous. Overloading can cause tire
failure, affect vehicle handling, and
increase the stopping distance. Use
tires of the recommended load
capacity for your vehicle. Never
overload them.
Department of Transportation
Uniform Tire Quality Grades
The following tire grading categories
were established by the National
Highway Traffic Safety Administration.
The specific grade rating assigned by
the tire's manufacturer in each
category is shown on the sidewall of
the tires on your vehicle.
All passenger car tires must conform
to Federal safety requirements in
addition to these grades.
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
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, however, and may depart
significantly from the norm due to
variations in driving habits, service
practices, and differences in road
characteristics and climate.
Traction Grades
The Traction grades, from highest to
lowest, are AAA, A, B, and C. These
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.
WARNING!
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.
Temperature Grades
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
conditons 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.
Driving
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