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:
Band selection
Push the “SAT” button when the radio is
off to turn on the radio.
Push the “SAT” button when the radio is
on to select SAT1, SAT2 or SAT3 reception. ...
Recommended grade and viscosity
Each oil manufacturer has its own base oils and additives. Never use different
brands together. For details, refer to “Manual transmission, front differential
and rear differential gear oil” F12-6 ...
System monitors
A diagnostic system continually monitors the readiness of the seatbelt pretensioner while the vehicle is being driven. The seatbelt pretensioners share the control module with the SRS airbag system.
...
