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Lubricating Machinery and Automotive Bearings – Key Factors to Consider When Choosing Grease


Lubricants, including grease, play a critical role in optimizing the performance and prolonging the lifespan of automotive and machinery bearings.

First, lubricants help minimize friction between bearings and its components by providing a protective film, which, in turn, ensures optimal performance, thus preventing downtime. 

Second, lubricants help prevent overheating by dissipating the heat produced once individual components come into contact with one another.

Lastly, lubricants help prolong the lifespan of bearing products by protecting them against contaminants, moisture, and corrosion. 

Grease as a lubricant

Grease has two main components – a base oil  and thickeners like metal soaps, organic, and inorganic materials. Grease may also contain additives like fillers, antioxidants, anti-corrosion, and anti-wear materials. The chemical composition of grease usually varies depending on the NLGI grade and application where the grease is ought to be used.

In terms of lubrication efficiency, the base oil plays a more important role while the thickeners boost the performance of the base oil.

Selecting the right type of grease

With the different types of lubricants and grease available to choose from, it can be a bit of a challenge for a non-technical person to distinguish which grease applies in specific applications. In order to minimize confusion, here are some tips from a trusted bearings supplier which has a strong global footprint in providing technical services.


Not all grease works on general applications as all types have mainly distinctive chemical formulae that work best on certain applications. The best way to prevent bearing failure is by determining the suitable greases type works perfectly for your application – is it multi-purpose? Is it for heavy duty or high speed machinery or car? 

Operating Environment Temperature

High temperature increases the risk of leakage, which, in turn, causes damage not just to the bearing but to the spare parts nearest to it. If the equipment is used in a high-temperature environment, choose a grease that contains polyurea or PTFE as thickeners with semi-synthetic or perfluorinated polyether synthetic base oils  since these are specially formulated for such – conditions. 

Compatibility (Miscibility)

Check  the manufacturer’s material safety data sheet (MSDS) or contact the distributor nearest you  to ensure that the grease that you will use won’t have any problems mixing with the original one in the bearings. Just remember, some types of grease are not compatible with others and mixing them may cause an adverse chemical reaction leading to premature failure.

NLGI consistency rating

The NLGI consistency rating is a system used internationally to measure the softness of a grease. The higher the rating, the firmer the grease is.

Bearing speed

The higher the speed of the bearings, the higher the temperature generated. For such application, it is critical to choose a grease that has lithium/calcium as thickener and ester + SHC as base oil that are capable of  providing a cooling effect.

Beware of overgreasing

Knowing how much grease to apply is just as important as knowing which type to use. When applying grease on bearings, do not fall into the trap of thinking “more” is better as over-greasing can lead to a few problems. These include overheating, collapsed seals, and consequently-failure.

Furthermore, overgreasing is simply wasteful. Excess grease will only be pushed out by the bearing elements as they turn.

How do you ensure that you are applying the right amount of grease?

Typically, most sealed bearings come pre-lubricated with 25 to 30 percent grease fill. This should be your target.

Do not leave everything to guesswork. Resist the urge to apply grease prior to the use of equipment or until it oozes out of the seals. Remember, when the seal is compromised, there is a much higher risk for the contaminants to get into the bearing components, which can then lead wear and fatigue flaking (spalling).

  • Consider using grease guns with pressure gauges. The pressure gauges will tell you if there is any abnormal back pressure, which is a sign that enough grease has been applied.
  • In order to ensure the proper distribution of grease, pump the grease slowly with a few seconds interval.
  • Finally, to make sure that everything is going to seamlessly work, make sure that you clean the exhaust ports, removing debris and hard crusts which can block passageways.
  • Use other grease tools from trusted manufacturers

For most people, it’s easy to think that applying grease is as simple as counting 1-2-3. Little does everyone know that having a basic knowledge about the technical advantage of lubrication solutions can save one establishment from encountering multiple technical problems in their machines or vehicles in the near future. 

It is also highly recommended to keep a record of assets with bearings which should include the date of the last inspection by a licensed mechanic and the application of grease apart from  other important notes.


Hassanein Alwan is the Managing Director of Mineral Circles Bearings with more than 10 years’ experience in the bearing industry’s technical support division, sales and marketing, plus strategic business development consultancy.