Department Of Transportation Uniform Tire Quality Grades; Traction Grades; Treadwear; Temperature Grades - Alfa Romeo Stelvio 2019 User Manual

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 vehicle 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
216
practices, and differences in road
characteristics and climate.

Traction Grades

The Traction grades, from highest to
lowest, are AA, 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
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
vehicle tires must meet under the
Federal Motor Vehicle Safety
Standard No. 109. Grades B and A
represent higher levels of
performance on the laboratory test
wheel, than the minimum required by
law.
Warning!
The temperature grade for this tire
is established for a tire that is
properly inflated and not
overloaded. Excessive speed,
under-inflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.