2017 MERCEDES-BENZ CLA ECU

Overinflated tires may: R
increase the braking distance R
adversely affect handling R
wear excessively and/or unevenly R
have an adverse effect on ride comfort R
be more susceptible to damage
Maximum tire pressures
C
Example: maximum permissible tire pres-
sure
Never exceed the maximum permissible tire
inflation pressure. Always observe the recom-
mended tire pressure for your vehicle when
adjusting the tire pressure ( Y
page 285).
i The actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration.
Checking the tire pressures
Important safety notes Observe the notes on tire pressure
( Y
page 285).
Information on air pressure for the tires on your
vehicle can be found: R
on the vehicle's Tire and Loading Information
placard on the B-pillar R
in the tire pressure table in the fuel filler flap
( Y
page 138)R
in the "Tire pressure" section Checking tire pressures manually To determine and set the correct tire pressure,
proceed as follows: X
Remove the valve cap of the tire that is to be
checked. X
Press the tire pressure gauge securely onto
the valve. X
Read the tire pressure and compare it to the
recommended value on the Tire and Loading
Information placard or the tire pressure table
( Y
page 285). X
If the tire pressure is too low, increase the tire
pressure to the recommended value. X
If the tire pressure is too high, release air. To
do so, press down the metal pin in the valve,
using the tip of a pen for example. Then check
the tire pressure again using the tire pressure
checker. X
Screw the valve cap onto the valve. X
Repeat these steps for the other tires.
Tire pressure loss warning system
(Canada only)
General notes While the vehicle is in motion, the tire pressure
loss warning system monitors the set tire pres-
sure using the rotational speed of the wheels.
This enables the system to detect significant
pressure loss in a tire. 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 display.
You can recognize the tire pressure loss warning
by the Run Flat Indicator Active Press
'OK' to Restart message in the multifunction
display in the Serv. menu. Information on the
message display can be found in the "Restarting
the tire pressure loss warning system" section
( Y
page 289).
Important safety notes
The tire pressure warning system does not warn
you of an incorrectly set tire pressure. Observe
the notes on the recommended tire pressure
( Y
page 285).
The tire pressure loss warning does not replace
the need to regularly check the tire pressure. An
even loss of pressure on several tires at the288
Tire pressure
Wheels and tires

PSI (pounds per square inch) A standard unit of measure for tire pressure.
Aspect ratio Relationship between tire height and tire width
in percent.
Tire pressure This is pressure inside the tire applying an out-
ward force to each square inch of the tire's sur-
face. 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.
Cold tire pressure The tires are cold: R
if the vehicle has been parked with the tires
out of direct sunlight 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
parts and more than 2.3 kg (5 lbs). These
optional extras, such as high-performance
brakes, level control, a roof rack or a high-per-
formance battery, are not included in the curb
weight and the weight of the accessories.
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 pur-
chasers. The TIN is made up of the manufactur-
er'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 capa-
city 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 distrib-
uted over the tire tread. If the tire tread is level
with the bars, the wear limit of

Tire-mounting tools should not be used near
the valve. This could damage the electronic
components.
Only have tires changed at a qualified spe-
cialist workshop.
Observe the instructions and safety notes in the
"Changing a wheel" section ( Y
page 301).
The wear patterns on the front and rear tires
differ, depending on the operating conditions.
Rotate the wheels before a clear wear pattern
has formed on the tires. Front tires typically
wear more on the shoulders and the rear tires in
the center.
On vehicles that have the same size front and
rear wheels, you can rotate the wheels accord-
ing to the intervals in the tire manufacturer's
warranty book in your vehicle documents. If no
warranty book is available, the tires should be
rotated every 3,000 to 6,000 miles (5,000 to
10,000 km). Depending on tire wear, this may
be required earlier. Do not change the direction
of wheel rotation.
Clean the contact surfaces of the wheel and the
brake disc thoroughly every time a wheel is rota-
ted. Check the tire pressure and, if necessary,
restart the tire pressure loss warning system
(Canada only) or the tire pressure monitor (USA
only).
Direction of rotation Tires with a specified direction of rotation have
additional benefits, e.g. if there is a risk of hydro-
planing. These advantages can only be gained if
the tires are installed corresponding to the
direction of rotation.
An arrow on the sidewall of the tire 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 tires
from oil, grease, gasoline and diesel. Mounting a wheel
Preparing the vehicle X
Stop the vehicle on solid, non-slippery and
level ground. X
Apply the electric parking brake manually. X
Bring the front wheels into the straight-ahead
position. X
Shift the transmission to position P .X
Switch off the engine. X
Vehicles without KEYLESS-GO: remove the
SmartKey from the ignition lock. X
Vehicles with KEYLESS-GO start-function
or KEYLESS-GO: open the driver's door.
The vehicle electronics now have status 0 .
This is the same as the SmartKey having been
removed. X
Vehicles with KEYLESS-GO start-function
or KEYLESS-GO: remove the Start/Stop but-
ton from the ignition lock ( Y
page 121).X
Make sure that the engine cannot be started
via your smartphone ( Y
page 122).X
If included in the vehicle equipment, remove
the tire-change tool kit from the vehicle. X
Safeguard the vehicle against rolling away
( Y
page 140).
Securing the vehicle to prevent it from
rolling away
If your vehicle is equipped with a wheel chock, it
can be found in the tire-change tool kit
( Y
page 266).
The folding wheel chock is an additional safety
measure to prevent the vehicle from rolling
away, for example when changing a wheel.302
Changing a wheel
Wheels and tires

Always pay attention to the instructions and
safety notes in the "Changing a wheel" section
( Y
page 301).
Only use wheel bolts that have been designed
for the wheel and the vehicle. For safety rea-
sons, Mercedes-Benz recommends that you
only use wheel bolts which have been approved
for Mercedes-Benz vehicles and the respective
wheel.
! To prevent damage to the paintwork, hold
the wheel securely against the wheel hub
while screwing in the first wheel bolt.
X
Clean the wheel and wheel hub contact sur-
faces. X
Place the new wheel on the wheel hub and
push it on. X
Tighten the wheel bolts until they are finger-
tight.
Lowering the vehicle
G WARNING
The wheels could work loose if the wheel nuts
and bolts are not tightened to the specified
tightening torque. There is a risk of accident.
Have the tightening torque immediately
checked at a qualified specialist workshop
after a wheel is changed. X
Place the ratchet wrench onto the hexagon
nut of the jack so that the letters AB are visi-
ble. X
Turn the ratchet wrench until the vehicle is
once again standing firmly on the ground. X
Place the jack to one side. X
Tighten the wheel bolts evenly in a crosswise
pattern in the sequence indicated ( C to