Process, Controls & Plant Focus on: Seals, Bearings & Lubrication 22 | Plant & Works Engineering www.pwemag.co.uk Annual Buyers’Guide 2026 Chris Johnson, managing director of bearing specialist SMB Bearings, explores the advantages and limitations of grease and oil lubrication methods. Choosing the right lubricant for your application According to Siemens report The true cost of downtime, the annual cost of an idle production line at a major automotive facility has surged to $695 million — one and a half times higher than five years ago. In heavy industry, downtime now costs $59 million annually, a 1.6-fold increase since 2019. While bearing failures are relatively rare, improper lubrication remains a key contributor. Choosing between grease and oil isn’t straightforward — it depends on factors such as speed, load, temperature, orientation, and contamination. These rising costs underscore just how critical it is to prevent avoidable equipment failures — but how often do production managers consider the critical role of industrial bearings in ensuring equipment longevity? When applying industrial bearings, few choices are as important as the choice between grease and oil lubrication. Grease and oil share the same fundamental purpose, and each play an essential role in reducing friction, minimising wear and extending bearing life. That said, the conditions in which they operate best are very different. Put simply, making the wrong bearing lubrication choice can lead to overheating, premature failure or unplanned downtime. In order to avoid these consequences, let’s look at how production managers can choose the best lubricant — and avoid the cost of equipment downtime. Where grease excels Grease has a thicker consistency than oil. It is usually a base oil suspended in a soap-like thickener, which helps it stay in place more easily — especially in vertically mounted or hard-to-reach locations. These characteristics make grease ideal for applications like electric motors, conveyor systems or food processing equipment where protection from washdown or particles is essential. Grease also acts as a sealant, helping to keep out dirt, moisture and other contaminants. It is typically easier to apply and less prone to leakage, which makes it a cost-effective solution for sealed or shielded bearings that aren’t regularly maintained. Grease is often the preferred choice in applications that require simplicity, longer service intervals or operate in environments where lubricant retention would otherwise be a challenge. However, grease also has its limitations. It doesn’t dissipate heat as efficiently as oil and can break down faster in high-speed or hightemperature environments. In such cases, excessive heat can cause the thickener to degrade, which reduces lubrication effectiveness and potentially damages the bearing. When oil is the better fit Oil is often favoured in very high-speed or low torque applications where better cooling and continuous circulation are needed. Unlike grease, oil can be pumped, filtered and monitored as part of a closed lubrication system — which allows contaminants to be removed and fresh lubricant to be supplied continuously. Typical examples include gearboxes, machine tools and high-speed spindles. In these cases, the superior heat transfer properties of oil reduce the risk of thermal damage and prolong bearing life. Oil also provides lower friction in many situations, making it well-suited to precision applications that demand tight tolerances and consistent performance. That said, oil systems are more complex and require careful design. They need pumps, reservoirs, filtration units and regular monitoring. Some applications require a continuous oil mist or oil spray — all of which add to maintenance requirements and cost. They’re also less effective in vertical or exposed environments where leakage or oil migration can become problematic. Key factors in the decision Several operating parameters should guide the decision between grease and oil lubrication, each with a direct impact on bearing performance. Speed is one of the most critical considerations — as rotational speed increases, so does friction and heat. In many high-speed
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