BMW 645Ci Coupe 2004 - Manual (Page 168)

Wheels and tires
166
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 ... 1204 indicates that a tire was man-
ufactured in week 12 of the year 2004.
BMW recommends for various reasons,
including beginning brittleness, replacing
all tires after 6 years at the latest, even if a
tire age of 10 years is possible.
Uniform Tire Quality Grading
Quality grades can be found where appli-
cable on the tire sidewall between tread
shoulder and maximum section width.
For example:
Treadwear 200 Traction AA
Temperature A
DOT Quality Grades
Treadwear
Traction AA A B C
Temperature A B C
All passenger car tires must conform
to Federal Safety Requirements in
addition to these grades. <
Treadwear
The treadwear grade is a comparative rat-
ing 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 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.
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 govern-
ment test surfaces 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 brak-
ing traction tests, and does not include
acceleration, cornering, hydroplaning, or
peak traction characteristics.
<
e.g.
Nominal width
in mm
Aspect ratio in X
Radial type
Rim diameter in inches
Load rating
not on ZR tires
Speed rating
before R on ZR tires
205/60 R 1 5 91 W
e.g.
Manufacturer code
for tire make
Tire size and tire design
Tire age
DOT xxxx xxx 1204
Online Edition for Part No. 01 41 0 157 980 - © 01/04 BMW AG