Aspect Ratio = (Section Height/Section Width) X 100
Deflection = Free radius minus loaded radius.
Free Radius = The radius of the tire/wheel assembly that is not deflected under load.
Loaded Radius = Distance from wheel axis of rotation to supporting surface at a given load and stated inflation pressure.
Loaded Section Height = The loaded radius minus half of the nominal rim diameter. Distance from rim seat to outer tread surface of a loaded tire.
Nominal Rim Diameter = Diameter of rim seat supporting the tire bead. Examples: 13", 15" and 16.5".
Overall Width = Maximum width in cross section of unloaded tire including protruding side ribs and decorations.
Revolutions Per Mile = Measured number of revolutions for a tire traveling one mile. This can vary with load and inflation.
Rim Width = Linear distance between rim flanges in contact with the tire.
Rolling Circumference = The linear distance traveled by a tire in one revolution. This can vary with load and inflation. Rolling circumference can be calculated as follows: 63,360 divided by revolutions per mile = rolling circumference in inches.
Section Height = Distance from rim seat to outer tread surface of unloaded tire.
Section Width = Linear distance between the outside sidewalls of an inflated tire without any load (exclusive of protruding side ribs and decorations).
Tread Width = The portion of the tread design which comes in contact with the road.
