Improved Lubricating Greases for Aircraft Wheel Bearings

Present day commercial aircraft wheel bearings are lubricated with greases approved under military specification MIL-G-81322 or greases developed for automotive and industrial use. Bearing builders, aircraft wheel manufacturers and airlines are seeking better greases to prolong the life of current bearings and provide protection under more severe future conditions. This paper compares laboratory test performance of current aircraft wheel bearing grease with next-generation, improved greases, demonstrating significant advantages for the new greases. Results from field tests conducted at a major commercial airline are included. The paper concludes that greases containing synthetic oils with a viscosity higher than MIL-G-81322 products are best for aircraft wheel bearings.