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 identification
1) Emission control label
2) Vehicle identification number
3) Certification and bar code label
4) Tire inflation pressure label
5) Vehicle identification number plate
6) Model number label
7) ...
The Inside
While it's possible to get fairly comfortable in many cars, it's not every
day that you feel like everything is right in terms of your driving position,
and that's how I felt in the Impreza 2.5GT. ...
Catalytic converter
WARNING
● Avoid fire hazards. Do not drive or park the vehicle anywhere near flammable
materials (e.g. grass, paper, rags or leaves), because the catalytic converter operates
at very high t ...
