Mercedes-Benz G-Class Operator's Manual page 267

If "T" precedes the size description: these are
compact emergency spare wheels at high tire
pressure, to be used only temporarily in an
emergency.
Tire width:tire width : shows the nominal tire
width in millimeters.
Height-width ratio: height-width ratio ; is the
ratio between tire height and tire width. The
aspect ratio is calculated by dividing the tire
width by the tire height. The resulting quotient is
given as a percentage.
Tire code: tire code = shows the tire type. "R"
represents radial tires; "D" represents diagonal
tires; "B" represents diagonal radial tires.
Optionally, tires with a maximum speed of over
149 mph (240 km/h) may have "ZR" in the size
description, depending on the manufacturer
(e.g. 245/40 ZR 18).
Rim diameter: rim diameter ? is the diameter
of the bead seat, not the diameter of the rim
flange. The rim diameter is specified in
inches (in).
The load-bearing index: load-bearing index A
(also load index), is a code that contains the
maximum load-bearing capacity of a tire.
Do not overload the tires by exceeding the
specified load limit. The maximum permissible
load can be found on the vehicle's Tire and
Loading Information placard on the B-pillar on
the driver's side ( page 260).
Y
Example:
Load-bearing index 91 indicates a maximum
load of 1,356 lb (615 kg) that the tires can bear.
Further information on the maximum tire load in
kilograms and pounds (
For further information on the load bearing
index, see "Load index" (
Speed rating:speed rating B specifies the
approved maximum speed of the tire.
i
Tire data is vehicle-specific and may deviate
from the data in the example.
Regardless of the speed rating, always observe
the speed limits. Drive carefully and adapt your
driving style to the traffic conditions.
i
Since 2009, tires in Europe which corre-
spond to the noise limitations of Directive
ECE-R 117 show an >>S<< (Sound) mark. This
marking is in accordance with the type
approval number and is not connected to the
speed rating.
page 266).
Y
page 266).
Y
All about wheels and tires
Summer tires
Index Speed rating
Q up to 100 mph (160 km/h)
R up to 106 mph (170 km/h)
S up to 112 mph (180 km/h)
T up to 118 mph (190 km/h)
H up to 130 mph (210 km/h)
V up to 149 mph (240 km/h)
W up to 168 mph (270 km/h)
Y up to 186 mph (300 km/h)
ZR...Y up to 186 mph (300 km/h)
ZR...(..Y) over 186 mph (300 km/h)
ZR over 149 mph (240 km/h)
Optionally, tires with a maximum speed of
R
over 149 mph (240 km/h) may have "ZR" in
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.
If the size description of your tire includes
R
"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 and the maximum
speed of the tire is limited to 186 mph
(300 km/h).
The size description for all tires with maxi-
R
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.
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Z