Tire Coding; Uniform Tire Quality Grading; Tire Identification Number - BMW 2008 Z4 Owner's Manual

Z4 Coupe 3.0si
Tire size
All pressure specifications in the table are
indicated in psi/kilopascal with cold tires,
cold = ambient temperature
225/45 R 17 91 W
225/45 R 17 91 H/V M+S
Front: 225/45 R 17 91W
Rear: 255/40 R 17 94 W
Front: 225/40 R 18 88 W
Rear: 255/35 R 18 90 W
You will find more information about permissible loads and weights on page 113.

Tire coding

Understanding the lettering on the tire sidewall
makes it easier to identify and choose the cor-
rect tires.
Tire size
e.g. 225/50 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 U.S. Department of Transportation.
86
Online Edition for Part no. 01 41 0 014 500 - © 08/07 BMW AG
Pressure specifications in psi/kPa
DOT code:
e.g.
Manufacturer's code
for tire make
Tire size and
tire design
Tire age
1
6 92 V
Tire age
The date on which the tire was manufactured is
indicated by the code on the sidewall:
DOT ... 5005 indicates that the tire was manu-
factured in week 50 of the year 2005.
BMW recommends the replacement of all tires
every 6 years at the latest, even if a tire usage of
10 years is possible.

Uniform Tire Quality Grading

Quality grades can be found where applicable
on the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA
Temperature A
DOT Quality Grades
Tread wear
Traction AA A B C
Temperature A B C
33/230
33/230
–
33/230
–
DOT xxxx xxx 5005
39/270
–
39/270
–
39/270