Porsche Cayenne Owner's Manual page 290

Example of Inscription
Inscription on radial tire
A Tire size
Example: P 255/55R18 109 Y
– P - The tire is designed for Passenger vehicle.
This information is not included on all tires.
– 255 - Indication of tire width in mm
– 55 - Indication of tire height to tire width ratio
in percent
– R - Belt type code letter for radial
290
Minor Repairs
– 18 - Indication of rim diameter in inches
– 109 - Load capacity coefficient
– Y - Speed code letter
– XL (Extra Load) - Tire with increased load
rating
B TIN (Tire Identification Number)
Example: DOT xx xx xxxx xxxx
– DOT
The DOT symbol indicates that the tires com-
ply with the requirements of the US Depart-
ment of Transportation and provides informa-
tion about:
– first two-digit code means manufacture's iden-
tification mark.
– second two-digit code means tire size.
– third four-digit code means tire type code.
– fourth four-digit code means date of manufac-
ture.
If, for example, the last four numbers read
1204, the tire was produced in the 12th week
of 2004.
C Tire ply composition and material
The number of layers in the tread and sidewalls
and their material composition.
D Maximum permissible inflation pressure
The maximum permissible cold inflation pressure
to which a tire can be inflated.
f Do not exceed the permissible inflation pres-
sure.
E Maximum Load rating
The maximum load in kilograms and pounds can
be carried by the tire. If you replace tires always
use a tire that has the same maximum load rating
as the factory installed tire.
F Radial
The identification indicates if the tire has radial
structure.
G Term of tubeless or tube tire
Identification for tubeless tires.