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:
Recommended shifting speeds
The best compromise between fuel economy and vehicle performance during normal driving is ensured by shifting up at the speeds listed in the following table.
...
Vehicle placard
The vehicle placard is affixed to the
driver’s side B-pillar.
Example:
The vehicle placard shows original
tire size, recommended cold tire
inflation pressure on each tire at
maximum load ...
Brake fluid level warning
This light illuminates when the brake fluid level has dropped
to near the “MIN” level of the brake fluid reservoir with the ignition switch in
the “ON” position and with the parking brake released ...
