To grease or not to grease!

Posted by Q8OilsMarketing on

Over-greasing vs under-greasing: which one does more damage?

When it comes to bearing lubrication, striking the right balance is crucial. But which is worse – over-greasing or under-greasing? The truth is, both can be equally damaging, and the bigger problem often depends on your specific application and maintenance setup.

Let’s unpack the risks and implications of each.

The Two Sides of the Greasing Coin

Over- and under-greasing don’t just refer to how much grease you apply during a service—they also relate to how often you grease. Applying too much grease or greasing too frequently can be as detrimental as applying too little or doing it too infrequently.

The Risks of Over-Greasing

Adding excessive grease to a bearing can:

  • Cause seal failure – If the bearing housing doesn’t have a relief port, pressure from too much grease can blow out the seals, leading to leaks and allowing contaminants to enter.
  • Generate excess heat – Unlike oil, grease cannot effectively dissipate heat. Overfilling the housing creates fluid friction, which leads to churning, heat build-up, and eventual grease breakdown.
  • Waste lubricant – If purge points are in place, excess grease will simply be flushed out—often including perfectly good grease.

The Dangers of Under-Greasing

Too little grease leads to:

  • Insufficient lubrication – Metal-on-metal contact causes friction, heat, and accelerated wear.
  • Contamination ingress – Gaps in the housing allow dust, moisture, and other harmful contaminants into the load zones.
  • Grease hardening – If bearings go ungreased for too long, the grease may oxidise and harden, reducing protection and increasing wear.

Which Is Worse?

While both conditions are harmful, not greasing frequently enough is generally considered more damaging. Over time, hardened grease and contaminant build-up can severely degrade bearing components.

Best Practice: Follow the Guidelines

Always refer to your equipment manufacturer’s lubrication recommendations. If unavailable, follow these two handy rules of thumb:

1. Greasing Frequency

Use a relubrication chart:

  • Start with your bearing speed (RPM).
  • Follow the graph up to intersect with your bearing I.D. (inner diameter).
  • Move left to find the recommended lubrication interval (in hours).

2. Grease Quantity Formula

To calculate the amount needed in grams:
Outer Diameter (mm) x Width (mm) x 0.005

Example:
A 6209 ball bearing (OD = 85mm, Width = 19mm) requires:
85 × 19 × 0.005 = 8 grams of grease every 10,000 hours.

If your grease gun dispenses 1.35g per stroke, that’s about 6 strokes every 13 months, or one stroke every 8 weeks.

Need Help Choosing the Right Grease?

Explore the full Blue Chip Lubricants grease portfolio:

Post Views: 433