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.
BeadThe 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 indicatorsNarrow 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 00CDin (1.6 mm)
has been reached.
Occupant distribution The distribution of occupants in a vehicle at theirdesignated seating positions.
Total load limit Nominal load and luggage load plus 68 kg
(150 lbs) multiplied by the number of seats in
the vehicle. Changing a wheel
Flat tire
The "Breakdown assistance" section
(Y page 241) contains information and notes on
how to deal with a flat tire. Information on driv-
ing with MOExtended tires in the event of a flat
tire can be found under "MOExtended tires (tires with run-flat characteristics" (Y page 242). Rotating the wheels
G
WARNING
Interchanging the front and rear wheels may
severely impair the driving characteristics if
the wheels or tires have different dimensions. The wheel brakes or suspension components
may also be damaged. There is a risk of acci-
dent.
Rotate front and rear wheels only if the wheels and tires are of the same dimensions.
! On vehicles equipped with a tire pressure
monitor, electronic components are located
in the wheel. Changing a wheel
275Wheels and tires Z
