Overall Width
The overall width of a tire is measured from the inner to the outer sidewall when mounted and inflated (this includes protective ribs/decorations). Section Width
The section width of a tire is measured from sidewall to sidewall when mounted and inflated, but not loaded (excludes protective ribs/decorations). Tread Width
The tread width is the distance measured from the outer edge to the inner edge of the tread. Rim Width
The rim width is the distance between the outer & inner rim flanges on which the tire beads seat. Free Radius
The free radius is the distance from the wheel axle centerline to the outer tread surface of the unloaded, properly inflated tire.
Static Loaded Radius
The static loaded radius is the distance from the wheel axle centerline to the tread contact surface. It’s measured after the tire has been mounted on its measuring rim, inflated to the test pressure and placed under a prescribed load. Overall Diameter
The overall diameter of a tire is the distance between the tire’s tread surfaces, measured at the widest point with the tire mounted and no load applied.
Section Height
The section height is a measure of the vertical distance between the tire’s bead seat and outer tread surface, when mounted and inflated, but with no load placed on the tire.
Rim Diameter
The rim diameter is the distance between the wheel’s bead seats.
