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 descrip-
tion (as shown above): these are passenger
vehicle tires according to European manufac-
turing standards.
If "P" precedes the size description: these are
passenger vehicle tires according to U.S. man-
ufacturing standards.
If "LT" precedes the size description: these are
light truck tires according to U.S. manufactur-
ing standards.
If "T" precedes the size description: compact
emergency wheels with high tire pressure that
are only designed for temporary use 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 in percent. 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 manufac-
turer (e.g. 245/40 ZR 18).
Rim diameter: rim diameter
?
is the diame-
ter 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 303).
Example:
Load-bearing index 91 indicates a maximum
load of 1,356 lb (615 kg) that the tires can
bear. For further information on the maximum
tire load in kilograms and lbs, see
(
Y
page 310).
For further information on the load bearing
index, see "Load index" (
Y
page 309).
Speed rating: speed rating
B
specifies the
approved maximum speed of the tire.
i
Tire data is vehicle-specific and may devi-
ate 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.
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)
308
All about wheels and tires
Whe
el
s
and
tire
s
Summary of Contents for SL 450 2019
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