DOT Tire Quality Grades
The tires on your car meet Federal Safety Requirements. AM tires
are also "graded" according to Department of Transportation (DOT) standards for tread wear, traction and temperature.
Three gradesare shown on the
tire sidewall
TIRE
WHEEL RIM
Tread Wear The tread wear 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 wearone 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
The traction grades, from highest to lowest, are A, B, and C, and they represent the tire's ability to stop on wet pavement asmeasured under controlled conditions on specified government test
surfaces of asphalt and concrete. A tire marked C may have poor
traction performance.
The traction grades assigned are based on braking (straight ahead) traction tests and do not include cornering (turning) traction.ProCarManuals.comMain Menu t s
