Temperature - SMART 2016 fortwo Owner's Manual

All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
i
The actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
U.S. government course. For example, a tire
graded 150 would wear one and one-half times
as well on the government test track as a tire
graded 100.
The relative performance of tires depends
upon the actual conditions of their use, how-
ever, and may depart significantly from the
norm due to variations in driving habits,
service practices and differences in road
characteristics and climate conditions.
Traction
G
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.
!
Avoid wheelspin. This can lead to damage
to the drive train.
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 safe speed on a wet, snow covered or icy
road is always lower than on dry road surfa-
ces.
You should pay special attention to road con-
ditions when temperatures are around freez-
ing point.
smart recommends a minimum tread depth of
ã in (4 mm) on all four winter tires. Observe
the legally required minimum tire tread
depth ( page 172). Winter tires can reduce
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the braking distance on snow-covered surfa-
All about wheels and tires
ces in comparison with summer tires. The
braking distance is still much further than on
surfaces that are not icy or covered with snow.
Take appropriate care when driving.
Further information on winter tires (M+S
tires) ( page 173).
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Temperature

G
WARNING
The temperature grade for this tire is
established for a tire that is properly
inflated and not overloaded. Excessive
speed, underinflation, or excessive load-
ing, either separately or in combination,
can cause excessive heat build-up and pos-
sible tire failure.
The temperature grades are A (the highest), B
and C. They represent 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
corresponds to a level of performance which
all passenger car 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.
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