BMW 645Ci Coupe 2005 - Manual (Page 171)

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Tire identification marks
Knowledge of the labeling on the side of the tire
makes it easier to identify and choose the right
tires.
Tire size
Speed letter
T = up to 118 mph/190 km/h
H = up to 131 mph/210 km/h
V = up to 150 mph/240 km/h
W = up to 167 mph/270 km/h
Y = up to 186 mph/300 km/h
Tire Identification Number
Tires with DOT codes meet the guidelines of
the U.S. Department of Transport.
DOT code:
Tire age
The tire's date of manufacture is indicated on
the sidewall:
DOT ... 3604 indicates that a tire was manufac-
tured in week 36 of the year 2004.
BMW recommends replacing all tires at least
every 6 years, even if some tires may last for
10 years.
Uniform Tire Quality Grading
Quality grades can be found where applicable
on the tire sidewall between tread shoulder and
maximum section width. For example:
Tread wear 200 Traction AA
Temperature A
DOT Quality Grades
Tread wear
Traction AA A B C
Temperature A B C
All passenger car tires must conform to
Federal 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 specified gov-
ernment test course.
For example, a tire graded 150 would wear one
and one-half, 1
γ, times as well on the govern-
ment 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 varia-
tions in driving habits, service practices and dif-
ferences in road characteristics and climate.
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 sur-
faces 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, cor-
nering, hydroplaning, or peak traction charac-
teristics.
<
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
e.g.
Nominal width
in mm
Aspect ratio in
Ξ
Radial type
Rim diameter in inches
Load rating
not on ZR tires
Speed rating
before R on ZR tires
205/60 R 15 91 W
e.g.
Manufacturer code
for tire make
Tire size and tire design
Tire age DOT xxxx xxx 3604
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