Page 224 of 290
Rear spoiler
Overview
The rear spoiler improves the handling of the
vehicle. It adapts the vehicle's aerodynamics to the operating conditions, dependent on the
speed of the vehicle.
Only use button :in the switch strip above the
overhead control unit to extend and retract the
rear spoiler manually for cleaning. Button :is
not used to operate the rear spoiler.
The rear spoiler is extended automatically if you
drive faster than:
R75 mph (120 km/h) in drive programs C,S
and S+
R44 mph (70 km/h) in drive program RACE
Button :flashes until the rear spoiler has
extended and then lights up in red.
The rear spoiler is retracted automatically when you drive slower than:
R50 mph (80 km/h) in drive programs C,S and
S+
R19 mph (30 km/h) in drive program RACE
Button :flashes until the rear spoiler has
retracted and then goes out.
Extending and retracting the rear
spoiler manually
GWARNING
Body parts could become trapped if you man-
ually retract the rear spoiler. There is a risk of
injury.
Make sure that nobody is within the range of
movement of the rear spoiler. Release the
switch immediately if somebody becomes
trapped. The rear spoiler then extends again.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
!Do not enter an automatic car wash with the
rear spoiler extended. Otherwise, the rear
spoiler may be damaged.
Only extend the rear spoiler in order to clean
it by hand. Retract it again when you have fin-
ished cleaning it.
You can extend and retract the rear spoiler man- ually for cleaning.
XClose the tailgate.
XSelect SmartKey position 2with the Start/
Stop button (Ypage 103).
XTo extend: press button :.
The rear spoiler is extended.
Button :flashes until the rear spoiler has
extended and then lights up in red.
XTo retract: press and hold button :until the
rear spoiler is completely retracted.
Button :flashes until the rear spoiler has
retracted and then goes out.
Rear Spoiler Retracts Manually
appears in the display.
If you release button :while retracting the rear
spoiler, it extends again automatically.
222Features
Stowage and features
Page 268 of 290
Vehicle identification plate
Even if you have calculated the total cargo care-
fully, you should still make sure that the gross
vehicle weight rating and the gross axle weight
rating are not exceeded. Details can be found on
the vehicle identification plate on the B-pillar on
the driver's side of the vehicle (
Ypage 263).
Permissible Gross Vehicle Weight Rating
(GVWR): the gross weight of the vehicle, all pas-
sengers, load and trailer load/noseweight (if
applicable) must not exceed the permissible
gross vehicle weight.
Gross Axle Weight Rating (GAWR): the maxi-
mum permissible weight that can be carried by
one axle (front or rear axle).
To ensure that your vehicle does not exceed the
maximum permissible values (gross vehicle
weight and maximum gross axle weight rating),
have your loaded vehicle (including driver, occu-
pants, cargo, and full trailer load if applicable)
weighed on a suitable vehicle weighbridge.
All about wheels and tires
Uniform Tire Quality Grading Stand-
ards
Overview of Tire Quality Grading Stand-
ards
Uniform Tire Quality Grading Standards are U.S.
government specifications. Their purpose is to
provide drivers with uniform reliable information
on tire performance data. Tire manufacturers
have to grade tires using three performance fac- tors: :tread wear grade, ;traction grade and
= temperature grade. These regulations do not
apply to Canada. Nevertheless, all tires sold in
North America are provided with the corre- sponding quality grading markings on the side-
wall of the tire.
Quality grades can be found, where applicable,
on the tire sidewall between tread shoulder and
maximum section width.
Example:
RTreadwear grade:
200
RTraction grade:AA
RTemperature grade: A
All passenger car tires must conform to the stat-
utory safety requirements in addition to these
grades.
iThe actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified U.S.
government course. For example, a tire graded
150 would wear one and one-half times as well
on the government course as a tire graded 100.
The relative performance of tires depends upon the actual conditions of their use, however, and
may depart significantly from the norm due to
variations in driving habits, service practices
and differences in road characteristics and cli-
mate.
Traction
GWARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction char-
acteristics.
!Avoid wheelspin. This can lead to damage to
the drive train.
The traction grades – from highest to lowest –
are AA, A, B and C. Those grades represent the
tire's ability to stop on wet pavement as meas-
ured under controlled conditions on specified
government test surfaces of asphalt and con-
crete. A tire marked C may have poor traction
performance.
The safe speed on a wet, snow covered or icy
road is always lower than on dry road surfaces.
266All about wheels and tires
Wheels and tires
Page 269 of 290
You should pay special attention to road condi-
tions when temperatures are around freezing
point.
Mercedes-Benz recommends a minimum tread
depth ofãin (4 mm) on all four winter tires.
Observe the legally required minimum tire tread
depth (
Ypage 255). Winter tires can reduce the
braking distance on snow-covered surfaces in
comparison with summer tires. The braking dis-
tance is still much further than on surfaces that
are not icy or covered with snow. Take appro-
priate care when driving.
Further information on winter tires (M+S tires)
(
Ypage 256).
Temperature
GWARNING
The temperature grade for this tire is estab-
lished for a tire that is properly inflated and
not overloaded. Excessive speed, underinfla-
tion, or excessive loading, either separately or
in combination, can cause excessive heat
build-up and possible tire failure.
The temperature grades are A (the highest), B,
and C, representing the tire's resistance to the
generation of heat and its ability to dissipate
heat when tested under controlled conditions
on a specified indoor laboratory test wheel. Sus-
tained high temperature can cause the material
of the tire to degenerate and reduce tire life, and
excessive temperature can lead to sudden tire
failure. The grade C corresponds to a level of
performance which all passenger car tires must
meet under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A represent
higher levels of performance on the laboratory
test wheel than the minimum required by law.
Tire labeling
Overview
:Uniform Tire Quality Grading Standard
(Ypage 271)
;DOT, Tire Identification Number
(Ypage 270)
=Maximum tire load (Ypage 269)
?Maximum tire pressure (Ypage 259)
AManufacturer
BTire material (Ypage 270)
CTire size designation, load-bearing capacity
and speed rating (Ypage 267)
DLoad index (Ypage 269)
ETire name
The markings described above are on the tire in
addition to the tire name (sales designation) and
the manufacturer's name.
iTire data is vehicle-specific and may deviate
from the data in the example.
Tire size designation, load-bearing
capacity and speed rating
GWARNING
Exceeding the stated tire load-bearing capa-
city 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
All about wheels and tires267
Wheels and tires
Z