- 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.
