What is the typical lubricant choice for rolling-element bearings in mechanical drives?

• A. Solid dry lubricant only
• B. No lubrication is needed
• C. Grease (per bearing manufacturer) or oil, depending on bearing design
• D. Only water-based lubricant

Answer: (C)

Lubrication is essential for rolling-element bearings to minimize wear and manage heat. In mechanical drives, the typical approach is to use grease or oil, chosen based on the bearing design and operating conditions. Sealed or shielded bearings are often pre-filled with grease, which provides a maintenance-friendly, long-interval solution. For higher speeds, higher temperatures, or open bearings in circulating lubrication systems, oil is preferred because it can carry away heat more effectively and support higher-speed performance. Solid dry lubricants may be used in special cases (extreme temperatures, clean environments, or vacuum) but aren’t the common choice for typical drives. Water-based lubricants aren’t standard due to insufficient film strength and corrosion concerns, and bearings do require lubrication rather than none.