Ford 1999 F-350, Owner'S Manual

Page: 190 / 248

INFORMATION ABOUT TIRE QUALITY GRADES
New vehicles are fitted with tires
that have their Tire Quality Grade
(described below) molded into the
tire’s sidewall. These Tire Quality
Grades are determined by standards
that the United States Department
of Transportation has set.
Tire Quality Grades apply to new
pneumatic tires for use on
passenger cars. They do not apply
to deep tread, winter-type snow
tires, space-saver or temporary use spare tires, tires with nominal rim
diameters of 10 to 12 inches or limited production tires as defined in
Title 49 Code of Federal Regulations Part 575.104(c)(2).
U.S. Department of Transportation-Tire quality grades: The U.S.
Department of Transportation requires Ford to give you the following
information about tire grades exactly as the government has written it.
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, however, and may depart significantly from the
norm due to variations in driving habits, service practices, and
differences in road characteristics and climate.
Traction AA A B C
The traction grades, from highest 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. A tire marked C may have poor traction
performance.
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.
Maintenance and care
190