Temperature – A, B and C
The temperature grades are A (the highest), B and C,
representing the tire’s resistance to generate heat and to
dissipate heat when tested under controlled conditions
on a specified indoor laboratory test wheel. Sustained
high temperatures can cause the material of the tire to
degenerate and reduce tire life, and excessive
temperature can lead to sudden tire failure. Grade C
corresponds to a level of performance that all
passenger vehicle tires must meet under the Canadian
Motor Vehicle Safety Standard No. 109. Grades A and
B represent higher levels of performance on the
laboratory test wheel than the maximum required by
law.
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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 wear one-and-a-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. Variations in driving
habits, service practices and differences in road
characteristics and climate may significantly affect
performance.
Traction – A, B and C
The traction grades, from highest to lowest, are A, B
and C, and they 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 -Tire Temperature
The temperature grade for a tire is established
for a tire that is properly inflated and not
overloaded. Excessive speed, underinflation, or
excessive loading, either separately or in
combination, can cause heat build-up and
possible sudden tire failure. This can cause loss
of vehicle control and death or personal injury.
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