Assuming the inside cut edge, or starting of the bead bundle, to be positioned at the twelve o'clock position, a clockwise wrap of the bead ribbon would result in the outside cut edge being found at the one o'clock position. This area of overlap between the twelve and one o'clock position is called the bead splice. Virtually every tire bead failure occurs in the location of bead splice at the inside cut edge of the five wires that start the bead. Each of these strong wires, commonly .037 inches in diameter, is individually capable of holding 300 pounds and separated into two well constructed beads, these wires can easily hold 7 tons of air pressure, providing they are all carrying an equal load. But when the wires in the grommet become unstabilized and distorted the combined strength of the bead grommet is lost.
Preventable distortion can occur when the bead is being seated onto the rim of a drop center wheel.
The drop center, or smaller interior portion of the wheel, is the feature which allows a tire to be button-holed over the outer rim flange. Drop centers are found on every passenger and light truck wheel. In mounting these tires, the rim flange is detached, the tire placed on the wheel, the outer rim is re-attached and then the tire is inflated. Distortion in the bead grommet naturally occurs in this process if the area of the bead splice happens to be the last portion of the bead to seat. One explanation for this fact is that a splice, by definition, is always a weakest point and prone to separation and distortion.