Operation Manual

the size description, depending on the man-
ufacturer (e.g. 245/40 ZR18).
The service specification is made up of load-
bearing index A and speed rating B.
R
If the size description of your tire includes
"ZR" and there are no service specifications,
ask the tire manufacturer in order to find out
the maximum speed.
If a service specification is available, the max-
imum speed is limited according to the speed
rating in the service specification. Example:
245/40 ZR18 97 Y. In this example, "97 Y" is
the service specification. The letter "Y" rep-
resents the speed rating. The maximum
speed of the tire is limited to 186 mph
(300 km/h).
R
The size description for all tires with maxi-
mum speeds of over 186 mph (300 km/h)
must include "ZR", and the service specifica-
tion must be given in parentheses. Example:
275/40 ZR 18 (99 Y). Speed rating "(Y)" indi-
cates that the maximum speed of the tire is
over 186 mph (300 km/h). Ask the tire man-
ufacturer about the maximum speed.
All-weather tires and winter tires
Index Speed rating
Q M+S
1
up to 100 mph (160 km/h)
T M+S
1
up to 118 mph (190 km/h)
H M+S
1
up to 130 mph (210 km/h)
V M+S
1
up to 149 mph (240 km/h)
i
Not all tires with the M+S marking provide
the driving characteristics of winter tires. In
addition to the M+S marking, winter tires also
have the i snowflake symbol on the tire
wall. Tires with this marking fulfill the require-
ments of the Rubber Manufacturers Associa-
tion (RMA) and the Rubber Association of
Canada (RAC) regarding the tire traction on
snow. They have been especially developed
for driving on snow.
An electronic speed limiter prevents your vehi-
cle from exceeding a speed of 130 mph
(210 km/h).
The speed rating of tires mounted at the factory
may be higher than the maximum speed that the
electronic speed limiter permits.
Make sure that your tires have the required
speed rating, e.g. when buying new tires. The
required speed rating for your vehicle can be
found in the "Tires" section (
Y page 277).
Further information about reading tire data can
be obtained from any qualified specialist work-
shop.
Load index
In addition to the load-bearing index, load
index : may also be imprinted on the sidewall
of the tire. You will find this after the letter that
identifies the speed rating (
Y page 267).
R
If no specification is given: no text (as in the
example above), represents a standard load
(SL) tire
R
XL or Extra Load: represents a reinforced tire
R
Light Load: represents a light load tire
R
C, D, E: represents a load range that depends
on the maximum load that the tire can carry at
a certain pressure
i
Tire data is vehicle-specific and may deviate
from the data in the example.
Maximum load rating
1
Or M+S i for winter tires.
All about wheels and tires
269
Wheels and tires
Z