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:
Breaking-in of new brake pads and linings
When replacing the brake pad or lining, use only genuine SUBARU parts. After replacement, the new parts must be broken in as follows. ...
Tire inspection
Check on a daily basis that the tires are free from serious damage, nails, and
stones. At the same time, check the tires for abnormal wear.
Contact your SUBARU dealer immediately if you find any pr ...
MMT
Some gasoline contains an octane-enhancing additive called MMT (Methylcyclopentadienyl
Manganese Tricarbonyl). If you use such fuels, your emission control system performance
may deteriorate and t ...
