Department Of Transportation - Aston Martin DB11 Owner's Handbook Manual

US Department of Transportation
Uniform Tire Quality Grades
The following information relates to the tire grading system
developed by the National Highway Traffic Safety
Administration, which grades tires by tread wear, traction and
temperature performance. All passenger vehicle tires must
conform to federal safety requirements in addition to these
grades.
Tread Wear
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 (1½) 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
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.
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
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 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.
Maintenance and Technical Data
12.19