2012 MERCEDES-BENZ A CLASS Owners Manual

wheels and tyres for damage. Hidden tyre
damage could also be causing the unusual
handling characteristics. If you find no
signs
of damage, have the wheels and tyres
checked at a qualified specialist workshop.
R When parking your vehicle, make sure that
the tyres do not get deformed by the kerb
or other obstacles. If it is necessary to drive
over kerbs, speed humps or similar eleva-
tions, try to do so slowly and at an obtuse
angle. Otherwise, the tyres, particularly the
sidewalls, may be damaged. Regular checking of wheels and tyres
G
WARNING
Damaged tyres can cause tyre inflation pres-
sure loss. As a result, you could lose control
of your vehicle. There is a risk of accident.
Check

the tyres regularly for signs of damage
and replace any damaged tyres immediately.
Regularly check the wheels and tyres of your
vehicle for damage at least once a month, as
well as after driving off-road or on rough
roads. Damaged wheels can cause a loss of
tyre pressure. Pay particular attention to
damage such as:
R cuts in the tyres
R punctures
R tears in the tyres
R bulges on tyres
R deformation or severe corrosion on wheels
Regularly check the tyre tread depth and the
condition of the tread across the whole width
of the tyre (Y page 319). If necessary, turn
the front wheels to full lock in order to inspect
the inner side of the tyre surface.
All wheels must have a valve cap to protect
the valve against dirt and moisture. Do not fit
anything onto the valve other than the stand-
ard valve cap or other valve caps approved by
Mercedes-Benz for your vehicle. Do not fit any
other valve caps or systems, e.g. tyre pres-
sure monitoring systems. Regularly check the pressure of all the tyres,
particularly

prior to long trips. Adjust the tyre
pressure as necessary ( Y page 321).
Observe the notes on the emergency spare
wheel (Y page 332).
The service life of tyres depends on various
factors, including the following:
R driving style
R tyre pressure
R tyre mileage Tyre tread
G
WARNING
Insufficient tyre tread will reduce tyre trac-
tion. The tyre is no longer able to dissipate
water.

This means that on wet road surfaces,
the risk of aquaplaning increases, in particular
where speed is not adapted to suit the driving
conditions. There is a risk of accident.
If the tyre pressure is too high or too low, tyres
may exhibit different levels of wear at differ-
ent locations on the tyre tread. Thus, you
should regularly check the tread depth and
the condition of the tread across the entire
width of all tyres.
Minimum tyre tread depth for:
R summer tyres: 3 mm
R M+S tyres: 4 mm
For safety reasons, replace the tyres before
the legally prescribed limit for the minimum
tyre tread depth is reached.. Selecting, fitting and replacing tyres
R Only fit tyres and wheels of the same type
and make.
Exception:

it is permissible to fit a different
type or make in the event of a flat tyre.
Observe the "MOExtended tyres (tyres with
run-flat characteristics)" section
(Y page 300).
R Only fit tyres of the correct size onto the
wheels. Operation
319
Wheels and tyres Z

R
Run in new tyres at moderate speeds for
the first 100 km
. They only reach their full
performance after this distance.
R Do not drive with tyres which have too little
tread depth. This otherwise significantly
reduces the traction on wet roads (aqua-
planing).
R Replace the tyres after six years at the lat-
est, regardless of wear.
Observe the notes on the emergency spare
wheel (Y page 332). MOExtended tyres (tyres with run-flat
characteristics)
With MOExtended tyres (tyres with run-flat
characteristics), you can continue to drive
your vehicle even if there is a total loss of
pressure in one or more tyres.
MOExtended tyres may only be used in con-
junction with an active tyre pressure loss
warning system and only on wheels specifi-
cally tested by Mercedes-Benz.
Notes

on driving with MOExtended tyres with
a flat tyre ( Y page 300).
i Vehicles with MOExtended tyres are not
equipped with a TIREFIT kit at the factory.
It is therefore recommended that you addi-
tionally equip your vehicle with a TIREFIT kit
if you fit tyres that do not feature run-flat
characteristics, e.g. winter tyres. A TIREFIT
kit can be obtained from a qualified spe-
cialist 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 324). Driving with summer tyres
At temperatures below +7 †, summer tyres
lose elasticity and therefore traction and
braking

power. Change the tyres on your vehi-
cle to M+S tyres. Using summer tyres at very
cold temperatures could cause tears to form,
thereby damaging the tyres permanently.
Mercedes-Benz cannot accept responsibility
for this type of damage. M+S tyres
G
WARNING
M+S
tyres with a tyre tread depth of less than
4 mm are not suitable for use in winter as they
do not provide sufficient traction. There is a
risk of accident.
M+S tyres with a tread depth of less than
4 mm must be replaced.
At temperatures below +7 †, use winter tyres
or all-season tyres. Both types of tyre are
identified by the M+S marking.
Only winter tyres bearing the i snowflake
symbol in addition to the M+S marking pro-
vide the best possible grip in wintry road con-
ditions. Only these tyres will allow driving
safety systems such as ABS and ESP ®
to
function optimally in winter. These tyres have
been developed specifically for driving in
snow.
Use M+S tyres of the same make and tread
on all wheels to maintain safe handling char-
acteristics.
Always observe the maximum permissible
speed specified for the M+S tyres you have
fitted.
If you fit M+S tyres that have a lower maxi-
mum permissible speed than that of the vehi-
cle, affix an appropriate warning sign in the
driver's field of vision. This can be obtained
at a qualified specialist workshop.
Under these circumstances, you should also
restrict the maximum speed of the vehicle
using permanent SPEEDTRONIC so that it 320
Winter operation
Wheels and tyres

does not exceed the maximum permissible
speed for the M+S tyres(Y page 172).
When you have fitted the M+S tyres:
X
Check the tyre pressures ( Y page 321).
X Restart the tyre pressure loss warning sys-
tem (Y page 323).
For more information on driving with the
emergency spare wheel, see (Y page 332). Snow chains
G
WARNING
If snow chains are fitted to the rear wheels,
they may scrape against the vehicle body or
chassis components. This could cause dam-
age

to the vehicle or the tyres. There is a risk
of an accident.
To avoid hazardous situations:
R never fit snow chains on the rear wheels
R always fit snow chains in pairs to the front
wheels.
! Vehicles with steel wheels: if you fit
snow chains on steel wheels, you may dam-
age the hub caps. Remove the hub caps
from the relevant wheels before fitting 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 that are of a corre-
sponding standard of quality.
If you intend to fit snow chains, please bear
the following points in mind:
R snow chains cannot be fitted to all wheel-
tyre combinations. Permissible wheel-tyre
combinations (Y page 329).
R only use snow chains when the road sur-
face is completely snow-covered. Remove
the snow chains as soon as possible when
you come to a road that is not snow-cov-
ered. R
local regulations may restrict the use of
snow

chains. Observe the appropriate reg-
ulations if you wish to fit snow chains.
R do not exceed the maximum permissible
speed of 50 km/h.
R when snow chains are fitted, never use
Active Parking Assist (Y page 186).
i You may wish to deactivate
ESP ®
(Y page 65) when pulling away with
snow chains fitted. This way you can allow
the wheels to spin in a controlled manner,
achieving an increased driving force (cut-
ting action).
Information about driving with an emergency
spare wheel ( Y page 332). Tyre pressure
Tyre pressure specifications
G
WARNING
Tyres with too low or too high tyre pressure
contain the following hazards:
R they

can burst, in particular if the vehicle is
heavily laden or when driven at high
speeds.
R the tyres can wear excessively and/or
unevenly, which can severely impair tyre
traction.
R the driving, steering and braking character-
istics may be severely impaired.
There is a risk of accident.
Follow recommended tyre inflation pressures
and check the pressure of all the tyres includ-
ing the spare wheel:
R at least every two weeks
R if the load changes
R before beginning a long journey
R for changed operating conditions, e.g. off-
road driving
If necessary, correct the tyre pressure. Tyre pressure
321
Wheels and tyres Z

G
WARNING
If you fit unsuitable accessories onto tyre
valves, the tyre valves may be overloaded and
malfunction, which can cause tyre pressure
loss. Due to their design, retrofitted tyre pres-
sure monitors keep the tyre valve open. This
can also result in tyre pressure loss. There is
a risk of accident.
Only screw standard valve caps or valve caps
specifically provided by Mercedes-Benz for
your vehicle onto the tyre valve. G
WARNING
If the tyre pressure drops repeatedly, the
wheel, valve or tyre may be damaged. Tyre
pressure that is too low may result in a tyre
blow-out. There is a risk of accident.
R Check the tyre for foreign objects.
R Check

whether the wheel is losing air or the
valve is leaking.
If you are unable to rectify the damage, con-
tact a qualified specialist workshop. H
Environmental note
Check the tyre pressure regularly, at least
every 14 days
.
You will find a table of tyre pressures for var-
ious operating conditions on the inside of
your vehicle's fuel filler flap.
Operation with an emergency spare
wheel (Y page 332).
Operation with a trailer: the applicable
value for the rear tyres is the maximum tyre
pressure value stated in the table inside the
fuel filler flap.
The table inside the fuel filler flap may state
tyre pressures for different load conditions.
These are defined in the table as different
numbers of passengers and amounts of lug-
gage. The actual number of seats may vary;
for more information, please refer to the vehi-
cle's registration documents.
If tyre sizes are not specified, the tyre pres-
sures stated on the tyre pressure information label apply for all tyres approved for this vehi-
cle.
If a tyre size precedes a tyre pressure, the
following tyre pressure information is only
valid for that tyre size.
Use a suitable pressure gauge to check the
tyre

pressure. The outer appearance of a tyre
does not permit any reliable conclusion about
the tyre pressure.
If possible, only correct tyre pressures when
the tyres are cold.
The tyres are cold:
R if the vehicle has been parked with the tyres
out of direct sunlight for at least three
hours and
R if the vehicle has not been driven further
than 1.6 km
Depending on the ambient temperature, the
speed at which you are driving and the load
on the tyres, the tyre temperature and thus
the tyre pressure change by approximately
10 kPa per 10 † (0.1 bar/1.5 psi). Take this
into account when checking the pressure of
warm tyres. Only correct the tyre pressure if
it is too low for the current operating condi-
tions.
Driving with tyre pressure that is too high or
too low can:
R shorten the service life of the tyres
R cause increased tyre damage
R have a negative effect on handling charac-
teristics and thus the driving safety (e.g.
aquaplaning)322
Tyre pressure
Wheels and tyres

i
The tyre pressure values given for low
loads are minimum values which offer you
good ride comfort characteristics.
However,
you can also use the values given
for higher loads. These are permissible and
will not adversely affect the running of the
vehicle. Tyre pressure loss warning system
Important safety notes While the vehicle is in motion, the tyre pres-
sure loss warning system monitors the set
tyre pressure using the rotational speed of
the

wheels. This enables the system to detect
significant pressure loss in a tyre. If the speed
of rotation of a wheel changes as a result of
a loss of pressure, a corresponding warning
message will appear in the multifunction dis-
play.
The tyre pressure warning system does not
warn you of an incorrectly set tyre pressure.
Observe the notes on the recommended tyre
pressure ( Y page 321).
The tyre pressure loss warning system does
not replace the need to regularly check your
vehicle's tyre pressures, since an even loss of
pressure on several tyres at the same time
cannot be detected by the tyre pressure loss
warning system.
The tyre pressure monitor is not able to warn
you of a sudden loss of pressure, e.g. if the
tyre is penetrated by a foreign object. In the
event of a sudden loss of pressure, bring the
vehicle to a halt by braking carefully. Avoid
abrupt steering manoeuvres.
The function of the tyre pressure loss warning
system is limited or delayed if:
R snow chains are fitted to your vehicle's
tyres.
R road conditions are wintry.
R you are driving on sand or gravel.
R you adopt a very sporty driving style (cor-
nering at high speeds or driving with high
rates of acceleration). R
you
are towing a very heavy or large trailer.
R you are driving with a heavy load (in the
vehicle or on the roof).
Restarting the tyre pressure loss warn-
ing system Restart the tyre pressure loss warning system
if you have:
R
changed the tyre pressure
R changed the wheels or tyres
R fitted new wheels or tyres
X Before restarting, make sure that the tyre
pressures

are set properly on all four tyres
for the respective operating conditions.
The recommended tyre pressures can be
found in the table on the fuel filler flap.
The tyre pressure loss warning system can
only give reliable warnings if you have set
the correct tyre pressure. If an incorrect
tyre pressure is set, these incorrect values
will be monitored.
X Observe the notes on tyre pressure
(Y page 321).
X Make sure that the key is in posi-
tion 2(Y page 143) in the ignition lock.
X Press the =
or ; button on the steer-
ing wheel to select the Service menu.
X Press the 9 or : button to select
Tyre pressure.
X Press the a button.
The Run Flat Indicator active
Restart

with OK message appears in the
multifunction display.
If you wish to confirm the restart:
X Press the a button.
The Tyre press. now OK? message
appears in the multifunction display.
X Press the 9 or : button to select
Yes.
X Press the a button.
The Run Flat Indicator restarted
message appears in the multifunction dis-
play. Tyre pressure
323
Wheels and tyres Z

After a teach-in period, the tyre pressure
loss warning system will monitor the set
tyre pressures of all four tyres.
or
If you wish to cancel the restart:
X Press the % button.
or
X If the Tyre press. now OK? message
appears, use the 9 or : button to
select Cancel.
X Press the a button.
The tyre pressure values stored at the last
restart will continue to be monitored. Changing a wheel
Flat tyre
You can find information on what to do in the
event of flat tyre in the "Flat tyre" section
(Y page 300). You will also find information
on driving with MOExtended tyres in the event
of a flat tyre.
Vehicles with an emergency spare
wheel: in the event of a flat tyre, the emer-
gency spare wheel is fitted according to the
description under "Fitting a wheel"
(Y page 325). Interchanging the wheels
G
WARNING
Interchanging the front and rear wheels may
severely impair the driving characteristics if
the

wheels or tyres have different dimensions.
The wheel brakes or suspension components
may also be damaged. There is a risk of acci-
dent.
Interchange front and rear wheels only if the
wheels and tyres are of the same dimensions.
Interchanging the front and rear wheels of
differing dimensions can render the general
operating permit invalid. Always pay attention to the instructions and
safety notes when changing a wheel
(Y page 324).
The

wear patterns on the front and rear tyres
differ, depending on the operating conditions.
Interchange the wheels before a clear wear
pattern has formed on the tyres. Front tyres
typically wear more on the shoulders and the
rear tyres in the centre.
On vehicles that have the same size front and
rear wheels, you can interchange the wheels
every 5,000km to 10,000 km depending on
the degree of tyre wear. Maintain the direc-
tion of tyre rotation.
Clean the contact surfaces of the wheel and
the brake disc thoroughly every time a wheel
is interchanged. Check the tyre pressure and,
if necessary, restart the tyre pressure loss
warning system. Direction of rotation
Tyres with a specified direction of rotation
have

additional benefits, e.g. if there is a risk
of aquaplaning. You will only gain these ben-
efits if the correct direction of rotation is
observed.
An arrow on the sidewall of the tyre indicates
its correct direction of rotation. Storing wheels
Store
wheels that are not being used in a cool,
dry and preferably dark place. Protect the
tyres against oil, grease, petrol and diesel. Cleaning the wheels
G
WARNING
The water jet of circular-jet nozzles (dirt grind-
ers) can cause damage not visible from the
outside

to tyres or chassis components. Com-
ponents damaged in this way can unexpect-
edly fail. There is a risk of an accident. 324
Changing a wheel
Wheels and tyres

Do not use high-pressure cleaners with circu-
lar-jet
nozzles to clean the vehicle. Have dam-
aged tyres or chassis components replaced
immediately. Fitting a wheel
Preparing the vehicle X
Stop the vehicle on solid, non-slippery and
level ground.
X Apply the electric parking brake manually
(Y page 163).
X Bring the front wheels into the straight-
ahead position.
X Vehicles with manual transmission:
engage first or reverse gear.
X Vehicles with automatic transmission:
move the DIRECT SELECT lever to P.
X Switch off the engine.
X Remove the key from the ignition lock.
X If a trailer is coupled to the vehicle, uncou-
ple it.
X If included in the vehicle equipment,
remove the tyre-change tool kit from the
vehicle.
X Secure the vehicle to prevent it from rolling
away.
i Apart
from certain country-specific varia-
tions, vehicles are not equipped with a tyre-
change tool kit. For information on which
tools are required to perform a wheel
change on your vehicle, consult a
Mercedes-Benz Service Centre.
Necessary wheel-changing tools can
include, for example:
R Jack
R Wheel chock
R Wheel wrench Securing the vehicle against rolling
away
If your vehicle is equipped with a wheel chock,
it can be found in the tyre-change tool kit
(Y page 299).
The folding wheel chock is an additional
securing

measure to prevent the vehicle from
rolling away, for example when changing a
wheel.
X Fold both plates upwards :.
X Fold out lower plate ;.
X Guide the lugs on the lower plate fully into
the openings in base plate =. Securing the vehicle on level ground
X
On level ground: place chocks or other
suitable items under the front and rear of
the wheel that is diagonally opposite the
wheel you wish to change. Changing a wheel
325
Wheels and tyres Z

Securing the vehicle on slight downhill gradients
X
On light downhill gradients: place
chocks or other suitable items in front of
the wheels of the front and rear axle.
Raising the vehicle G
WARNING
If you do not position the jack correctly at the
appropriate jacking point of the vehicle, the
jack could tip over with the vehicle raised.
There is a risk of injury.
Only
position the jack at the appropriate jack-
ing point of the vehicle. The base of the jack
must be positioned vertically, directly under
the jacking point of the vehicle.
Observe the following when raising the
vehicle:
R to raise the vehicle, only use the vehicle-
specific jack that has been tested and
approved by Mercedes-Benz. If the jack is
used incorrectly, it could tip over while the
vehicle is raised.
R the jack is designed only to raise and hold
the vehicle for a short time while a wheel
is being changed. It is not suitable for per-
forming maintenance work under the vehi-
cle.
R avoid changing the wheel on uphill and
downhill slopes.
R before raising the vehicle, secure it from
rolling away by applying the parking brake
and positioning wheel chocks. Never
release the parking brake while the vehicle
is raised. R
the jack must be placed on a firm, flat and
non-slip surface. On a loose surface, a
large,

load-bearing underlay must be used.
On a slippery surface, a non-slip underlay
must be used, e.g. rubber mats.
R do not use wooden blocks or similar
objects as a jack underlay. Otherwise, the
jack will not be able to achieve its load-
bearing capacity due to the restricted
height.
R make sure that the distance between the
underside of the tyres and the ground does
not exceed 3 cm.
R never place your hands or feet under the
raised vehicle.
R never lie under the raised vehicle.
R never start the engine when the vehicle is
raised.
R never open or close a door or the tailgate
when the vehicle is raised.
R make sure that no persons are present in
the vehicle when the vehicle is raised. Steel wheel with wheel trim
X
Vehicles with steel wheels: carefully
reach into two of the wheel trim openings
and remove the wheel trim.
Vehicles with hub caps:
the hub cap covers
the wheel bolts. Before you can unscrew the
wheel bolts, you must remove the hub cap. 326
Changing a wheel
Wheels and tyres