Tire Dimensions & Measurement Definitions  
ASPECT
RATIO = Section Height
xl00 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 SECTlON 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 DIAMETER = The diameter of the inflated tire without any load. 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. 
Report created on: 8/22/2014
Tire Information Center
Phone: 561.997.9229
