lubricate any tire bead with grease. Do not use lubricants  with magnesium alloy wheels. Most radial tires are mounted  without lubricant. The airframe manufacturer may specify  lubrication for a radial tire in a few cases. Aircraft tire and wheel assemblies are subject to enormous  stress while in service. Proper mounting ensures tires perform to  the limits of their design. Consult and follow all manufacturer’s  service information including bolt torques, lubrication and  balancing requirements, and inflation procedures.  As mentioned, a wheel assembly that is to have a tire  mounted upon it must be thoroughly inspected to ensure  it is serviceable. Pay close attention to the bead seat area,  which should be smooth and free from defects. The wheel  half mating surface should be in good condition. The O-ring  should be lubricated and in good condition to ensure it  seals the wheel for the entire life of the tire. Follow the  manufacturer’s instructions when inspecting wheels and the  tips provided earlier in this chapter.  [Figure 13-153] When the wheel halves and tires are ready to be mounted,  thought must be given to tire orientation and the balance  marks on the wheel halves and tire. Typically, the tire serial  number is mounted to the outboard side of the assembly. The  marks indicating the light portion of each wheel half should  be opposite each other. The mark indicating the heavy spot  of the wheel assembly should be mounted aligned with the  light spot on the tire, which is indicated by a red mark. If  the wheel lacks a mark indicating the heavy spot, align the  red spot on the tire (the light point) with the valve fitting  location on the wheel. A properly balanced tire and wheel  assembly improves the overall performance of the tire. It  promotes smooth operation free from vibration, which results  in uniform tread wear and extended tire life.  A final inspection of the tire to be mounted should be made.  Most important is to check that the tire is specified for the  aircraft application. It should say tubeless on the sidewall.  The part number, size, ply rating, speed rating, and technical  standard order (TSO) number should also be on the sidewall  and be approved for the aircraft installation. Visually check  the tire for damage from shipping and handling. There should  be no permanent deformation of the tire. It should pass  all inspections for cuts and other damage discussed in the  previous sections of this chapter. Clean the tire bead area with  a clean shop towel and soap and water or denatured alcohol.  Inspect the inside of the tire for condition. There should be  no debris inside the tire.  When assembling the wheel halves, follow manufacturer’s  instructions for tie bolt tightening sequences and torque  specification. Anti-seize lubricants and wet-torque values  are common on wheel assemblies. Use a calibrated hand  torque wrench. Never use an impact wrench on an aircraft  tire assembly. Tire beads are sometimes lubricated when mounted on  aluminum wheels. Follow the manufacturer’s instructions  and use only the non-hydrocarbon lubricant specified. Never  For the initial inflation of an aircraft tire and wheel assembly,  the tire must be placed in a tire inflation safety cage and  treated as though it may explode due to wheel or tire failure.  The inflation hose should be attached to the tire valve stem,  and inflation pressure should be regulated from a safe  distance away. A minimum of 30 feet is recommended. Air  or nitrogen should be introduced gradually as specified.  Dry nitrogen keeps the introduction of water into the tire  to a minimum, which helps prevent corrosion. Observe  the tire seating progress on the wheel rim while it inflates.  Depressurize the tire before approaching it to investigate  any observed issue.  [Figure 13-154] Aircraft tires are typically inflated to their full specified  operating pressure. Then, they are allowed to remain with no  load applied for 12-hours. During this time, the tire stretches,  and tire pressure decreases. A 5-10 percent reduction is  normal. Upon bringing the tire up to full pressure again, less  than 5 percent loss per day of pressure is allowable. More  should be investigated. Wheel and tire inspection should precede the mounting of  any tire, including tube-type tires. The tube to be installed  must also pass inspection and must be the correct size for  the tire and tire must be specified for the aircraft. Tire talc  13-90 Tube-Type Tires Tubeless Tires Figure 13-153.  The wheel half O-ring for a tubeless tire wheel  assembly must be in good condition and lubricated to seal for the  entire life of the tire. The mating surfaces of the wheel halves must  also be in good condition. 