Capacity and speed index, Wheels and tires, All about wheels and tires – Mercedes-Benz 2013 GL Class User Manual

Page 413

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Tire size designation, load-bearing

capacity and speed rating

G

WARNING

Exceeding the stated tire load-bearing
capacity and the approved maximum speed
could lead to tire damage or the tire bursting.
There is a risk of accident.
Therefore, only use tire types and sizes
approved for your vehicle model. Observe the
tire load rating and speed rating required for
your vehicle.

:

Tire width

;

Nominal aspect ratio in %

=

Tire code

?

Rim diameter

A

Load bearing index

B

Speed rating

General: depending on the manufacturer's

standards, the size imprinted in the tire wall
may not contain any letters or may contain
one letter that precedes the size description.
If there is no letter preceding the size
description (as shown above): these are
passenger vehicle tires according to
European manufacturing standards.
If "P" precedes the size description: these are
passenger vehicle tires according to U.S.
manufacturing standards.
If "LT" precedes the size description: these
are light truck tires according to U.S.
manufacturing standards.
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: aspect ratio ; is the
size ratio between the tire height and tire
width and is shown as a percentage. The
aspect ratio is calculated by dividing the tire
width by the tire height.
Tire code: tire code = specifies 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).
Load-bearing index: load-bearing index A
is a numerical code that specifies 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
(

Y

page 405).

Example:
The load bearing index 91 indicates a
maximum load of 1356 lb (615 kg) that the
tires can bear. For further information on the
maximum tire load in kilograms and pounds,
see (

Y

page 413).

For further information on the load bearing
index, see "Load index" (

Y

page 413).

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

All about wheels and tires

411

Wheels and tires

Z

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