BMW 4 Coupe Series Manual page 319

Tire age
Recommendation
Regardless of the tire tread depth, replace tires
at least every 6 years.
Manufacture date
You can find the manufacture date of the tire on
the tire sidewall.
Designation Manufacture date
DOT ... 1921 19th week 2021
Uniform Tire Quality Grading
Quality grades can be found where applicable on
the tire sidewall between tread shoulder and
maximum section width.
E.g.: Treadwear 200; Traction AA; Temperature
A
DOT Quality Grades
Treadwear
Traction AA A B C
Temperature A B C
All passenger vehicle tires must conform to Fed‐
eral Safety Requirements in addition to these
grades.
Treadwear
The 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. E.g., a tire graded 150
would wear one and one-half, 1 g, 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
may depart significantly from the norm due to
variations in driving habits, service practices and
differences in road characteristics and climate.
Online Edition for Part no. 01405A392C9 - VI/21
Wheels and tires
Traction
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 surfa‐
ces of asphalt and concrete. A tire marked C may
have poor traction performance.
The traction grade assigned to this tire is based
on straight-ahead braking traction tests, and
does not include acceleration, cornering, hydro‐
planing, or peak traction characteristics.
Temperature
The temperature grades are A, the highest, B,
and C, representing the tire's resistance to the
generation of heat and its ability to dissipate 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 exces‐
sive temperature can lead to sudden tire failure.
The grade C corresponds to a level of perform‐
ance which all passenger car tires must meet un‐
der the Federal Motor Vehicle Safety Standard
No. 109. Grades Band 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, underinflation, or
excessive loading, either separately or in com‐
bination, can cause heat buildup and possible
tire failure.
RSC – Run-flat tires
Run-flat tires, refer to page 323, are labeled with
a circular icon containing the letters RSC marked
on the sidewall.
MOBILITY
319