Concentric Bead Seating
The first step to balance any truck tire and wheel assembly is to ensure the beads are concentrically seated on the rim by measuring the distance between the rim flange edge and the molded rib (GG ring) on the lower sidewall (see Fig 1) If the distance between the rim flange edge and GG ring varies by more than 2/32", the tire must be demounted and inspected for any damage. The best method for ensuring concentric bead seating is to start with clean tire beads and bead seat areas on the rim. Approved tire mounting lubricant should be applied to the beads and to the rim immediately prior to mounting the tire. Technicians should make sure the lubricant does not dry prior to mounting the tire or seating the beads. See TMC RP 205D - USE OF TIRE BEAD LUBRICANTS , , and TMC's Radial Tire & Disc Wheel Service Manual.
After the tire has been mounted, the best practice is to seat the beads with the tire suspended and horizontal to the ground. If the beads are seated with tire in a vertical position, the possibility of non-concentrically seated beads will increase. It's also important to recognize that the maximum tire inflation pressure for seating the beads outside of a restraining device is five psi.
Some tires also have balance and run-out markings (also referred to as uniformity markings) on the side-wall to indicate if they should be mounted with these markings aligned with specific locations on the rim. For more information, refer to TMC RP 243A - TIRE AND WHEEL MATCH MOUNTING MARKINGS .