Table of Contents
Advertisement
Uniform t ire quality grading
- Tread wear
- Traction AA A BC
- Temperature ABC
Quality grades can be found where applicable
on the tire side wa ll between tread shoulder
and maximum section width c::> page 199 ,
fig . 152.
For example: Tread wear 200 , Traction AA,
Temperature A.
All passenger car tires must confo rm to Feder-
al Safety Requirements in addition to these
grades .
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 specif ied
government test course .
For example, a t ire graded 150 wou ld wear
one and one half (1 1/2) t imes as well on the
government course as a tire graded 100 .
The relati ve perfo rmance of ti res depends
upon t he actua l conditions of their use, how-
ever, and may depart sign ifican t ly from the
norm due to variations in driving habits, serv-
ice practices and differences in road character -
istics and climate.
Traction
The traction grades , from highest to lowest,
are AA, A, Band 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 c::>
&..
Temperature
The temperature grades are A (the highest),
B, and C, representing the tire's resistance to
the generat ion of heat and its ability to dissi-
pate heat when tested under controlled condi-
tions on a specified indoor laboratory test
wheel.
Tire s an d wheel s
203
Sustained high temperature can cause the
materia l of the tire to degenerate and reduce
tire life, and excessive temperat ure can lead
to sudden tire failure c::> &, .
The grade C corresponds to a level of perform -
ance which all passenger car tires must meet
under the Federal Motor Vehicle Safety Stand-
ard No. 109. Grades Band A represent higher
levels of performance on the laboratory test
whee l than the minimum required by law.
A
WARNING
The t raction grade assigned to th is tire is
based on straight-ahead braking traction
tests, and does not include accelerat ion,
cornering, hydroplaning or peak t raction
characterist ics.
A
WARNING
~
The temperature grade for this tire is es-
tablished for a tire that is properly inflated
and not overloaded . Excessive speed, un-
derinflation, or excessive loading, either
separately or in combinat ion, can cause
heat bui ldup and possible tire failure.
Winter tires
Winter tires can improve vehicle handling on
snow and ice. At temperatures below 45 °F
(7 °C) we recommend changing to winter
tires .
In some heavy snow areas, local governments
may require true w inter or "snow" t ires, those
with very deeply cut tread. These tires should
only be used in pairs and be installed on all
fou r wheels . Make sure you purchase snow
t ires that are t he same size and construction
type as t he othe r ti res on you r vehicle.
If your vehicle is equipped w it h all -wheel
drive*, th is w ill imp rove traction during winter
driv ing, even with the standa rd tires . Howev-
er, we strongly recommend that you always
equip all four whee ls on your vehicl e w ith cor-
rect ly fitted winter tires or all-season t i res,
when winter road conditions are expected .
ll-
•
•
Advertisement
Table of Contents
