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:
Keys
1) Master key
2) Submaster key
3) Valet key
4) Key number plate
5) Security ID plate
Three types of keys are provided for your vehicle:
Master key, submaster key and valet key. The master key ...
Most common causes of corrosion
The most common causes of corrosion are:
1. The accumulation of moisture retaining dirt and debris in body panel sections,
cavities, and other areas.
2. Damage to paint and other protective coatin ...
Channel preset
...
