suspension VOLVO XC70 2010 Owners Manual

06 Maintenance and specifications
Wheels and tires
06

251 Uniform Tire Quality Grading
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
TREADWEARThe treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified gov-
ernment test course. For example, a tire gra-
ded 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 many depart signifi-
cantly from the norm due to variation in driving
habits, maintenance practices and differences
in road characteristics and climate.
TRACTIONThe traction grades, from highest to lowest, are
AA, A, B, and C, as measured under controlled
conditions on specified government test sur-
faces of asphalt and concrete. A tire marked Cmay have poor traction performance. The trac-
tion grade assigned to this tire is based on
braking (straight-ahead) traction tests and is
not a measure of cornering (turning) 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.
TEMPERATUREThe 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 con-
ditions 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 corre-
sponds 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 per-
formance 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.
Snow chains, snow tires, studded tires
Snow chainsSnow chains can be used on your Volvo with
the following restrictions:
•Snow chains should be installed on front
wheels only. Use only Volvo approved
snow chains.
•If accessory, aftermarket or "custom" tires
and wheels are installed and are of a size
different than the original tires and wheels,
chains in some cases CANNOT be used.
Sufficient clearances between chains and
brakes, suspension and body components
must be maintained.
•Some strap-on type chains will interfere
with brake components and therefore
CANNOT be used.
•All Wheel Drive models: Snow chains
should only be installed on the front
wheels.
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