Frequently Asked Questions 

Do Timken® bearings come pre-lubricated?
Most Timken bearings are protected with a thin film preservative that, although excellent at preventing rust and corrosion, is not a lubricant. Because our preservative is compatible with most oils and greases, it is not necessary to clean the preservative off prior to adding lubricant. Timken also produces a wide range of special package bearing units that are "pre-lubricated" at the factory. These include "AP" Railroad bearings, automotive hub assemblies, housed units, wide inner ring ball bearings, pillow block units and some ball bearings. Because these units are pre-lubricated, it is not necessary to remove seals to add any additional grease. 


I saw the phrase “60 O.K. Timken Load” on a tube of lubrication. What does that mean?
Between 1935 and 1972, The Timken Company produced and sold a lubricant test machine that was used to determine the EP (extreme pressure) characteristics of grease and oil lubricants. It became an industry-standard test. A bearing race is mounted on a tapered arbor that is rotating at a high speed. A square, steel test block is then loaded against the rotating race, with the contact area flooded with the test lubricant. The load on the block is increased in increments until the oil film is broken and the spinning race produces a score mark on the test block. The load-value that produces the score is then called the Timken “O.K.” load rating.


It was generally assumed that the higher the O.K. value, the more load the lube could hold without the film strength being compromised. However, this is not necessarily the case, and the primary purpose of the test is to determine whether or not the lube has an EP additive. Values higher than 35 lbs. indicate the presence of an EP additive.


Do you recommend synthetic oil lubrication for your tapered roller bearings?
Timken has no objection to the use of synthetic lubricants with tapered roller bearings, provided they contain the proper additives for the specific application requirements. In some instances, synthetic greases are superior to petroleum-based oils in their ability to resist breakdown from mechanical and thermal conditions. However, the original equipment manufacturer should always be consulted concerning any change from a lubricant that is specified by them. Before using synthetic oil grease for your application, contact your sales or service engineer to be sure it is acceptable.


How do I know when to use grease with or without EP (extreme pressure) additives for my application?
EP additives are particularly beneficial in applications that experience high axial or thrust loads. However, bearing life testing actually shows reductions in fatigue life from using EP additives in some applications. We suggest greases with EP additives only for applications that have high axial or thrust loads. Many of our Timken greases come with EP additives for applications that demand it.


Could using the wrong grade lubricant instead of the manufacturer’s recommended grade be a cause of bearing failure?
Using the proper grade and type of lubricant is an important factor in bearing performance. Always follow original equipment manufacturers’ recommendations when making lubrication specifications. Failure to do so can lead to shortened bearing life and/or a risk of serious bodily harm.


What is the shelf life of your grease products?

The shelf life of most oils and greases manufactured by Timken is two years from the date of manufacture, provided that the oils and greases are properly stored in their original, unopened containers.

How do I clean the lubricant out of my bearing?

Start by wiping off all the oil or grease you can reach. Then, for mineral and synthetic oils and greases, wipe all surfaces with hydrocarbon solvent such as mineral spirits or kerosene, followed with an isopropyl alcohol wipe.

I’m using a competitor’s lubricant.  Do you offer a similar product?

Timken will likely have a functional equivalent to the lubricant you are using. In many cases, a superior product may be available at a competitive price. Please contact your Timken sales representative for more information.


I’ve noticed oil separation in my grease. Is it still OK to use?

Some oil separation or puddle formation seen on top of grease in pails or drums should not be a problem. Remember, a grease lubricates a bearing by releasing oil to the bearing contact, so releasing oil is a necessary function of the grease. Typically, the amount of oil separation is insignificant when compared with the mass of grease in the container. Normally, the separated oil can be safely stirred back into the bulk of the grease in the container. Experience has shown that much of this time-related oil separation can be reduced if the surface of the grease is kept smooth during storage (i.e., do not leave "craters" in the grease).


The grade or consistency of the grease is also related to oil separation. The lighter the grease grade, the more prone it becomes to oil bleed. 


Finally, large fluctuations in storage temperature can affect oil bleed.  Keep storage temperatures as consistent as possible.


The color of my oil/grease has darkened compared to when it was new. Is it still OK to use?

Yes, it’s still OK to use. Some oils and greases contain small amounts of additives that will darken with exposure to sunlight, UV light, temperature or air. Since this color change is the result of oxidation of the additives, which make up a very small portion of the oil or grease, there would be very little, if any, functional change to the lubricant.

What equipment should I use to automatically apply your product to my component?

Most greases and oils can be automatically dispensed.  Timken offers single- and multi-point lubricators to ensure proper bearing maintenance.  


Is there a problem with using a combination of two types of oils/greases in the same component where they may come in contact with each other? I want to replace the grease in an existing system with different grease. I can’t clean out all the old grease. Will there be a compatibility issue between the new and old grease?

As long as the two lubricants have similar thickener systems and base fluids, there should not be any compatibility issues. If there is a difference between the base fluid viscosities of the two lubricants, a mixture of the two will result in a base fluid viscosity somewhere between the two. A different viscosity oil may not cause compatibility problems, but it may result in performance problems. It is important to thoroughly clean or purge the old grease from the part to ensure that the new lubricant properties are not changed significantly as a result of being mixed with the old. Perfluoropolyethers and silicone based fluids should not be mixed with any other base fluids. Hydrocarbons (mineral and synthetic) and ester base fluids are somewhat compatible. Clay and conventional polyurea thickeners systems should not be mixed with any other thickener types or a softening or breakdown of the grease could occur.