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:
Tire rotation direction mark
Example of tire rotation direction mark
1) Front
If the tire has the rotation direction
specification, the tire rotation direction
mark is placed on its sidewall.
When you install a tire that ...
Tire pressures and wear
Maintaining the correct tire pressures
helps to maximize the tires’ service lives
and is essential for good running performance.
Check and, if necessary, adjust
the pressure of each tire (inclu ...
Safety
As mentioned, the Outback boasts excellent crash-test ratings and a better
rollover rating than an SUV. The standard stability system automatically means
there's antilock braking and traction cont ...
