Tire Identification Marks; Uniform Tire Quality Grading; Tire Identification Number - BMW 2006 325xi Owner's Manual

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
e.g. 225/45 R
Nominal width in mm
Aspect ratio in Ξ
Radial belt construction
Rim diameter in inches
Load rating,
not on ZR tires
Speed code letter, in
front of the R on ZR tires
Speed code letter
Q = up to 100 mph or 160 km/h
T = up to 118 mph or 190 km/h
H = up to 131 mph or 210 km/h
V = up to 150 mph or 240 km/h
W = up to 167 mph or 270 km/h
Y = up to 186 mph or 300 km/h

Tire Identification Number

Tires with DOT codes meet the guidelines of
the US Department of Transport.
DOT code:
e.g. DOT xxxx xxx 0705
Manufacturer's code
for tire make
Tire size and
tire design
Tire age
Tire age
The manufacturing date of tires is contained in
the tire coding: DOT ... 0705 means that the
tire was manufactured in week 7 of 2005.
BMW recommends that you replace all tires
after 6 years at most, even if some tires may last
for 10 years.
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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
1
7 91 V
Temperature A
DOT Quality Grades
Tread wear
Traction AA A B C
Temperature A B C
to these
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 (1γ) 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, how-
ever, and may depart significantly from the
norm due to variations in driving habits, service
practices and differences in road characteris-
tics 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.
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction charac-
teristics.<
All passenger car tires must conform to
Federal Safety Requirements in addition
grades.<
The traction grade assigned to this tire is
based on straight-ahead braking traction