Uniform Tire Quality Gradings - Volvo C70 Owner's Manual

Uniform tire quality gradings

ALL PASSENGER VEHICLE TIRES MUST
CONFORM TO FEDERAL SAFETY
REQUIREMENTS IN ADDITION TO THESE
GRADES
Quality grades can be found, where appli-
cable, on the tire sidewall between the
tread shoulder and maximum section
width. For example:
Treadwear 200 Traction AA
Temperature A
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, how-
ever, and many depart significantly from the
norm due to variation in driving habits, main-
tenance practices and differences in road
characteristics and climate.
TRACTION
The traction grades, from highest to lowest,
are AA, A, B, and C, as measured under con-
trolled conditions on specified government
test surfaces of asphalt and concrete. A tire
marked C may have poor traction perfor-
mance.
The traction grade assigned to this tire is
based on braking (straight-ahead) traction
tests and is not a measure of cornering (turn-
ing) traction.
WARNING
The traction grade assigned to this tire is
based on braking (straight-ahead) traction
tests and is not a measure of cornering
(turning) traction.
TEMPERATURE
The temperature grades are AA (the highest),
A, B, and C, representing the tire's resistance
to the generation of heat and its ability to dis-
sipate 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.
07 Wheels and tires

Uniform tire quality gradings

The grade C corresponds to a minimum level
of performance that all passenger vehicle
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.
WARNING
The temperature grade for this tire is estab-
lished for a tire that is properly inflated and
not overloaded. Excessive speed, under-
inflation, or excessive loading, either sepa-
rately or in combination, can cause heat
buildup and tire failure.
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