traction control MERCEDES-BENZ CLA-Class 2014 C117 User Guide

Treadwear indicators (TWI) are required by
law. Six indicators are positioned on the tire
tread. They are visible once the tread depth is
approximately 00CDin (1.6 mm). If this is the
case, the tire is so worn that it must be
replaced. Selecting, mounting and replacing
tires
R Only mount tires and wheels of the same
type and make.
Exception: it is permissible to install a dif-
ferent type or make in the event of a flat
tire. Observe the "MOExtended tires (tires
with run-flat characteristics" section
(Y page 297).
R Only mount tires of the correct size onto
the wheels.
R After mounting new tires, break them in at
moderate speeds for the first 60 miles
(100 km), as they only reach their full per-
formance after this distance.
R Do not drive with tires which have too little
tread depth, as this significantly reduces
the traction on wet roads (hydroplaning).
R Replace the tires after six years at the lat-
est, regardless of wear. MOExtended tires (tires with run-flat
properties)
With MOExtended tires (tires with run flat
characteristics), you can continue to drive
your vehicle even if there is a total loss of
pressure in one or more tires.
MOExtended tires may only be used in con-
junction with an active tire pressure monitor
and only on wheels specifically tested by
Mercedes-Benz.
Notes on driving with MOExtended tires with
a flat tire (Y page 297).
i Vehicles equipped with MOExtended tires
are not equipped with a TIREFIT kit at the
factory. It is therefore recommended that you additionally equip your vehicle with a
TIREFIT kit if you mount tires that do not
feature run-flat properties, e.g. winter tires.
A TIREFIT kit can be obtained from a quali- fied specialist workshop. Winter operation
General notes
Have your vehicle winterproofed at a qualified specialist workshop at the onset of winter.
Observe the notes in the "Changing a wheel"
section (Y page 336). Driving with summer tires
At temperatures below 45 ‡(+7 †), summer
tires lose elasticity and therefore traction and braking power. Change the tires on your vehi-cle to M+S tires. Using summer tires at very
cold temperatures could cause cracks to
form, thereby damaging the tires perma-
nently. Mercedes-Benz cannot accept
responsibility for this type of damage. G
WARNING
Damaged tires can cause tire inflation pres-
sure loss. As a result, you could lose control of your vehicle. There is a risk of accident.
Check the tires regularly for signs of damage
and replace any damaged tires immediately. M+S tires
G
WARNING
M+S tires with a tire tread depth of less than
00CF in (4 mm) are not suitable for use in winter
and do not provide sufficient traction. There is
a risk of an accident.
M+S tires with a tread depth of less than 00CFin
(4 mm) must be replaced immediately.
At temperatures below 45 ‡(+7 †), use win-
ter tires or all-season tires. Both types of tire are identified by the M+S marking. 316
Winter operationWheels and tires

Only winter tires bearing the
004Dsnowflake
symbol in addition to the M+S marking pro-
vide the best possible grip in wintry road con- ditions. Only these tires will allow driving
safety systems such as ABS and ESP ®
to
function optimally in winter. These tires have
been developed specifically for driving in
snow.
Use M+S tires of the same make and tread on
all wheels to maintain safe handling charac-
teristics.
Always observe the maximum permissible
speed specified for the M+S tires you have
mounted.
Once the winter tires are mounted:
X Check the tire pressures (Y page 320).
X Restart the tire pressure monitor
(Y page 323). Snow chains
G
WARNING
If snow chains are mounted on the rear
wheels, the snow chains could cause abrasion
to the vehicle body or to chassis components.
This could cause damage to the vehicle or the tires. There is a risk of an accident.
To avoid hazardous situations:
R never mount snow chains on the rear
wheels
R only mount snow chains in pairs on the
front wheels.
! On some tire sizes there is not enough
space for snow chains. To avoid damage to the vehicle or tires, observe the "Wheel and
tire combinations" section under "Tires and wheels".
! Vehicles with steel wheels:
if you
mount snow chains on steel wheels, you
may damage the hub caps. Remove the hub caps from the relevant wheels before
mounting the snow chains. For safety reasons, Mercedes-Benz recom-
mends that you only use snow chains that
have been specially approved for your vehicle by Mercedes-Benz, or are of a correspondingstandard of quality.
If you intend to mount snow chains, please
bear the following points in mind:
R Snow chains may not be mounted on all
wheel/tire combinations. Permissible
wheel-tire combinations (Y page 340).
R Only use snow chains when driving on
roads completely covered by snow.
Remove the snow chains as soon as possi- ble when you come to a road that is not
snow-covered.
R Local regulations may restrict the use of
snow chains. Observe the appropriate reg-
ulations if you wish to mount snow chains.
R Do not exceed the maximum permissible
speed of 30 mph (50 km/h).
R When snow chains are installed, never use
Active Parking Assist (Y page 181).
i You may wish to deactivate ESP ®
(Y page 68) when pulling away with snow
chains installed. You can thereby allow the
wheels to spin in a controlled manner, ach-
ieving an increased driving force (cutting
action). Tire pressure
Tire pressure specifications
G
WARNING
Underinflated or overinflated tires pose the
following risks:
R the tires may burst, especially as the load
and vehicle speed increase.
R the tires may wear excessively and/or
unevenly, which may greatly impair tire
traction.
R the driving characteristics, as well as steer-
ing and braking, may be greatly impaired.
There is a risk of an accident. Tire pressure
317Wheels and tires
Z

Uniform Tire Quality Grading Stand-
ards Overview of Tire Quality Grading
Standards
Uniform Tire Quality Grading Standards are
U.S. government specifications. Their pur-
pose is to provide drivers with uniform relia-
ble information on tire performance data. Tire
manufacturers have to grade tires using three
performance factors: tread wear 0043, tire trac-
tion 0044, and heat resistance 0087. These regu-
lations do not apply to Canada. Nevertheless,
all tires sold in North America are provided
with the corresponding quality grading mark- ings on the sidewall of the tire.
All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
Where applicable, the tire grading informa-
tion can be found on the tire sidewall between
the tread shoulder and maximum tire width.
i The actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
For example: Treadwear Traction Temperature
200 AA A
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, how-
ever, and may depart significantly from the
norm, due to variations in driving habits, ser-
vice practices and differences in road char-
acteristics and climate conditions. Traction
G
WARNING
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.
The traction grades, from highest to lowest,
are AA, A, B, and C. Those grades represent
the tire's ability to stop on a wet surface as
measured under controlled conditions on
specified government test surfaces of asphalt
and concrete. 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 surfa-
ces.
You should pay special attention to road con-
ditions when temperatures are around the
freezing point.
Mercedes-Benz recommends a minimum
tread depth of 00CFin (4 mm) for all four winter
tires (Y page 316) to maintain normal driving
characteristics in winter. Winter tires can
reduce the braking distance on snow-covered surfaces in comparison with summer tires.
Stopping distance, however, is still consider-
ably greater than when the road is not cov-
ered with ice or snow. Take appropriate care
when driving.
! Avoid wheelspin. This can lead to damage
to the drive train. 328
Uniform Tire Quality Grading StandardsWheels and tires

Tire pressure
This is pressure inside the tire applying an
outward force to each square inch of the tire's
surface. The tire pressure is specified in
pounds per square inch (psi), in kilopascal
(kPa) or in bar. The tire pressure should only
be corrected when the tires are cold. Tire pressure of cold tires
The tires are cold:
R if the vehicle has been parked without
direct sunlight on the tires for at least three
hours and
R if the vehicle has not been driven further
than 1 mile (1.6 km) Tread
The part of the tire that comes into contact
with the road. Bead
The tire bead ensures that the tire sits
securely on the wheel. There are several steel
wires in the bead to prevent the tire from
coming loose from the wheel rim. Sidewall
The part of the tire between the tread and the
bead. Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
part and more than 2.3 kg (5 lbs). These
optional extras, such as high-performance
brakes, level control, a roof rack or a high-
performance battery, are not included in the
curb weight and the weight of the accesso-
ries. TIN (Tire Identification Number)
This is a unique identifier which can be used
by a tire manufacturer to identify tires, for
example for a product recall, and thus identify the purchasers. The TIN is made up of the
manufacturer's identity code, tire size, tire
type code and the manufacturing date. Load bearing index
The load bearing index (also load index) is a
code that contains the maximum load bearing
capacity of a tire. Traction
Traction is the result of friction between the
tires and the road surface. Treadwear indicators
Narrow bars (tread wear bars) that are dis-
tributed over the tire tread. If the tire tread is level with the bars, the wear limit of 00CDin
(1.6 mm) has been reached. Occupant distribution
The distribution of occupants in a vehicle at
their designated seating positions. Total load limit
Nominal load and luggage load plus
68 kilograms (150 lb) multiplied by the num-
ber of seats in the vehicle. Changing a wheel
Flat tire
You can find information on what to do in the
event of a flat tire in the "Flat tire" section
(Y page 296). Information on driving with
MOExtended tires in the event of a flat tire can Changing a
wheel
335Wheels an d tires Z