Wheels
Wheel bolts The design of wheel bolts is matched to the
rims. If diff
er
ent wheel rims are fitted, the
correct wheel bolts with the right length and
correctly shaped bolt heads must be used.
This ensures that wheels are fitted securely
and that the brake system functions correctly.
In certain circumstances, you should not use
wheel bolts from a different vehicle, even if it
is the same model ››› page 259. WARNING
If the wheel bolts are not tightened correctly,
the wheel c ou
ld become loose while driving.
Risk of accident.
● The wheel bolts must be clean and turn
eas
ily. Never apply grease or oil to them.
● Use only wheel bolts which belong to the
wheel.
● If the pr
escribed torque of the wheel bolts
is t
oo low, they could loosen whilst the vehi-
cle is in motion. Risk of accident! If the tight-
ening torque is too high, the wheel bolts and
threads can be damaged. CAUTION
The prescribed tightening torque for wheel
bolt s
for steel and alloy wheels is 120 Nm. Tyre monitoring indicator*
Fig. 242
Centre console: tyre monitoring sys-
t em b
utt
on. The tyre monitoring system compares wheel
r
ev
o
lutions alongside the wheel diameter of
each wheel, with help from the ESC. If the di-
ameter of a wheel changes, the tyre monitor-
ing indicator lights up . The wheel diame-
ter changes when:
● Tyre pressure is insufficient.
● The tyre structure is damaged.
● The vehicle is unbalanced because of a
load.
● The wheel
s of one axle are under more
pres
sure (for example, driving with a trailer or
on steep slopes).
● The vehicle is fitted with snow chains.
● The temporary spare wheel is fitted.
● The wheel on one axle is changed. Tyre pressure adjustment
After modif
ying tyre pressure or changing any
wheels, the new tyre pressure must be stored
in the Easy Connect system with the but-
t on and the S
ET
TINGS function button
› ›
›
page 34.
You can also press and hold down the
››› Fig. 242 button with the ignition on, until
an acoustic signal is heard.
If the wheels are under excessive load (for ex-
ample, driving with a trailer or heavy load),
the tyre pressure must be increased to the
recommended value for a full load (see the
sticker on the back of the left front door
frame). If the tyre monitor system button is
pressed down, the new tyre pressures are
confirmed.
The tyre pressure control lamp lights up
If the tyre pressure of a wheel is much lower
than the value set by the driver, then the tyre
pressure control lamp ››› will light up.
WARNING
● When the tyr e pr
essure control lamp lights
up, reduce speed immediately and avoid any
sudden turning or braking manoeuvre. Stop
when possible, and check the tyre pressure
and status.
● The driver is responsible for maintaining
correct
tyre pressures. For this reason, tyre
pressure must be regularly checked. » 287
Technical data
Advice
Operation
Emergencies
Safety
Technical specifications
Drawbar loads
The maximum permitt ed dr
a
wbar load on the
ball coupling of the towing bracket must not
exceed 55 kg.
In the interest of road safety, we recommend
that you always tow approaching the maxi-
mum drawbar load. The response of the trail-
er on the road will be poor, if the drawbar
load is too small.
If the maximum permissible drawbar load
cannot be met (e.g. with small, empty and
light-weight single axle trailers or tandem
axle trailers with a wheelbase of less than 1
metre), a minimum of 4% of the actual trailer
weight is legally required for the drawbar
load. WARNING
● For s af
ety reasons, you should not drive at
speeds above 80 km/h (50 mph) when towing
a trailer. This also applies in countries where
higher speeds are permitted.
● Never exceed the maximum trailer weights
or the drawb
ar load. If the permissible axle
load or the permissible total weight is excee-
ded, the driving characteristics of the vehicle
may change, leading to accidents, injuries
and damage to the vehicle. Wheels
Ty
r
e pressure and wheel bolts Tyre pressure
The stic
k
er with the tyre pressure values can
be found on the back of the left front door
frame. The tyre pressure values given there
are for cold tyres. Do not reduce the slightly
raised pressures of warm tyres ››› .
The pre s
sure for winter tyres is 0.2 bar higher
than that of summer tyres (2.9 psi / 20 kPa).
Wheel bolts
After the wheels have been changed, the
tightening torque of the wheel bolts should
be checked as soon as possible with a torque
wrench ››› . The tightening torque for steel
and al lo
y
wheels is 120 Nm. WARNING
● Check the ty
re pressure at least once per
month. Checking the tyre pressure is very im-
portant. If the tyre pressure is too high or too
low, there is an increased danger of accidents
- particularly at high speeds.
● If the tightening torque of the wheel bolts
is t
oo low, they could loosen while the vehi-
cle is in motion. Risk of accident! If the tight-
ening torque is too high, the wheel bolts and
threads can be damaged. Note
We recommend that you ask your Technical
Serv ic
e for information about appropriate
wheel, tyre and snow chain size. 293
Technical data
Advice
Operation
Emergencies
Safety
