Bearing Maintenance & Lubrication: The Complete Guide

Up to 80% of premature bearing failures are caused by inadequate or improper lubrication. This guide covers everything you need to know about keeping your bearings running longer.

Why Lubrication Matters

Grease serves four critical functions in a bearing: - Reduces friction between rolling elements and raceways - Prevents metal-to-metal contact and wear - Protects against corrosion and contamination - Dissipates heat generated during operation

Choosing the Right Grease

Not all grease is created equal. Match these properties to your application: - Base oil viscosity: Higher viscosity for slower speeds and heavier loads - Thickener type: Lithium complex (general purpose), Polyurea (high-temp motors), Calcium sulfonate (wet environments) - Operating temperature range: Standard lithium grease works from -20°F to 250°F. High-temp applications need synthetic grease rated to 350°F+ - Speed rating (DN value): Bearing bore (mm) x RPM. Higher DN values need lighter grease

How Much Grease?

Over-greasing is just as damaging as under-greasing. It causes excessive heat, seal damage, and churning losses. - Rule of thumb: Fill bearing cavity 30-50% full - Relubrication amount (grams): 0.005 x D x B (where D = outside diameter in mm, B = bearing width in mm) - After greasing: Run the motor with the drain plug open for 30 minutes to purge excess grease

Relubrication Intervals

Intervals depend on speed, temperature, and contamination level. General guidelines: - Standard duty, clean environment: Every 6 months or 4,000 hours - Moderate duty, some contamination: Every 3 months or 2,000 hours - Heavy duty, dirty/dusty: Monthly or 750 hours - High temperature (>150°F): Monthly with high-temp grease - Wet/washdown: Weekly with water-resistant grease

Warning Signs of Lubrication Problems - Rising bearing temperature (measure with IR thermometer) - Increased noise or vibration - Grease discoloration (dark brown/black = overheating) - Grease leaking from seals - Visible rust or pitting on bearing surfaces

Need help setting up a lubrication program? Contact Service Bearing — we can recommend the right grease and schedule for every bearing in your facility.