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:
Flat tires
If you have a flat tire while driving, never brake suddenly; keep driving straight
ahead while gradually reducing speed. Then slowly pull off the road to a safe place. ...
Tire pressures
WARNING
Driving at high speeds with excessively low tire pressures can cause the tires
to deform severely and to rapidly become hot. A sharp increase in temperature could
cause tread separation, ...
Offroad Chops
The offroad portion of Subaru's press drive consisted of a lengthy course on
California's Catalina Island, and I had a chance to tackle some fairly
demolished dirt roads. I imagine a tiny fraction ...
