What property is important for the longevity of bearing performance?

Proper lubricant viscosity is crucial for the longevity of bearing performance because it directly affects the formation of a lubricating film between the moving parts of the bearing. This film helps to minimize metal-to-metal contact, thereby reducing friction, wear, and heat generation within the bearing. If the viscosity of the lubricant is too low, it may not provide sufficient cushioning and could lead to increased wear due to inadequate lubrication. Conversely, if the viscosity is too high, it could impede the smooth operation of the bearing by causing excessive drag.

Furthermore, maintaining the right viscosity ensures that the lubricant can flow well at operating temperatures while still providing a thick enough film during startup conditions. Therefore, proper lubricant viscosity is paramount in prolonging the life and reliability of bearings under varying operational circumstances.