Operation Manual

Some tire pressure tables show only the rim
diameters instead of the full tire size, e.g.
R18. Rim diameter is part of the tire size and
can be found on the tire sidewall
(Y page 315).
If the tire pressures have been set to the
lower values for lighter loads and/or lower
road speeds, the pressures should be reset to
the higher values:
R
if you want to drive with an increased load
and/or
R
if you want to drive at higher road speeds
i
The tire pressures for increased loads
and/or higher road speeds, shown in the
tire pressure table, may have a negative
effect on driving comfort.
If the tire pressure is not set correctly, this
can lead to an excessive build up of heat and
a sudden loss of pressure.
For more information, contact a qualified spe-
cialist workshop.
Important notes on tire pressure
G
WARNING
If the tire pressure drops repeatedly, the
wheel, valve or tire may be damaged. Tire
pressure that is too low may result in a tire
blow-out. There is a risk of an accident.
R
Check the tire 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.
G
WARNING
If you fit unsuitable accessories onto tire
valves, the tire valves may be overloaded and
malfunction, which can cause tire pressure
loss. Due to their design, retrofitted tire pres-
sure monitors keep the tire valve open. This
can also result in tire pressure loss. There is a
risk of an accident.
Only screw the standard valve cap or other
valve caps approved by Mercedes-Benz for
your vehicle onto the tire valve.
Use a suitable pressure gauge to check the
tire pressure. The outer appearance of a tire
does not permit any reliable conclusion about
the tire pressure. You can also check the tire
pressure using the on-board computer.
The tire temperature and pressure increase
when the vehicle is in motion. This is depend-
ent on the driving speed and the load.
Therefore, you should only correct tire pres-
sures when the tires are cold.
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)
The tire temperature changes depending on
the outside temperature, the vehicle speed
and the tire load. If the tire temperature
changes by 18 ‡ (10 †), the tire pressure
changes by approximately 10 kPa (0.1 bar/
1.5 psi). Take this into account when check-
ing the pressure of warm tires. Only correct
the tire pressure if it is too low for the current
operating conditions. If you check the tire
pressure when the tires are warm, the result-
ing value will be higher than if the tires were
cold. This is normal. Do not reduce the tire
pressure to the value specified for cold tires.
The tire pressure would otherwise be too low.
Tire pressure
305
Wheels and tires
Z