P Metric
With the P-Metric system, Section Width is measured in millimeters.
To convert millimeters into inches, divide by 25.4. The Aspect Ratio (Section Height divided by Section Width) helps provide more dimensional information about the tire size.
Example:

(1) P = Certain tire type used on light duty vehicles such as passenger cars
(2) Section Width in millimeters
(3) Aspect Ratio (= section height 7 section width).
(4) R = Radial Construction
(5) Rim diameter in inches
See also:
Vehicle Dynamics Control warning light
The Vehicle Dynamics Control system
provides its ABS control
through the electrical circuit of the
ABS system. Accordingly, if the ABS
is inoperative, the Vehicle Dynamics
Control system ...
Clutch pedal (MT models)
Check the clutch pedal free play and
reserve distance according to the maintenance
schedule in the “Warranty and
Maintenance Booklet”. ...
Exterior
To the outside observer, little distinguishes the Impreza's various trim
levels. The base side mirrors are black-colored and fold, and the door handles
are body-colored. Fifteen-inch steel wheels ...
