Bearing Lubrication Guide

Proper lubrication is the single most effective way to extend bearing life.

Grease vs Oil

Factor	Grease	Oil
Speed	Up to moderate	High speed, low friction
Temperature	-30degC to 120degC	Wider range
Maintenance	Sealed-for-life or periodic	Continuous circulation
Sealing	Helps block contamination	No sealing function
Cost	Lower	Higher (system required)

For most MRO applications, grease lubrication is standard.

How much grease

Over-greasing is as harmful as under-greasing. For standard bearings:

• Bearing cavity: 30-50% full
• Housing cavity: 30-40% full
• High speed (above 75% of limit): 20-30% full

Relubrication intervals

For bearings with grease nipples, relubricate at:

• Clean, moderate temperatures: every 2,000-4,000 hours
• Dusty or hot (>70degC): every 500-1,000 hours
• Vertical shaft: halve the interval

Grease compatibility

Do not mix grease types. Incompatible thickeners (e.g., lithium + sodium) can liquefy and leak out. If switching grease, purge the old grease completely.

Common greases for MRO

• Lithium-based NLGI 2: Standard for motors, pumps, fans up to 120degC.
• Polyurea: Longer life, higher temperature; common in electric motor factory fill.
• Synthetic (PAO base): For high temperature or extended intervals.