Taking a Risk with Non-OEM Bearings

John Deere OEM bearing AN212132 is a double-row bearing that is used in a variety of demanding applications such as grain drills, nutrient applicators, round balers, tillage implements, and planters.

Do non-OEM bearings sold by aftermarket companies meet the quality and design requirements as specified for John Deere OEM bearings? On the outside, it is difficult to tell the difference between the three bearings in the picture. So, John Deere wanted to know… What does the inside reveal?

That was the question posed to a reputable third-party engineering services company that specializes in bearing design and analysis. To answer that question, they did a complete, in-depth inspection of the John Deere AN212132 bearings compared to “equivalent” bearings sold by a distributor and a catalog company. They were asked to perform an unbiased, scientific analysis of randomly-selected bearing samples.

The remainder of this report summarizes the findings of their May 2009 study.

1.  Surface Finish:

Non-OEM bearing surface finishes are rougher than John Deere surface finishes. The catalog company outer raceway surface finishes are rougher than industry standards.

Customer Impact: Rough raceway surface finishes can inhibit the lubricate film between ball and raceway from developing, thus reducing life due to the increased metal-to-metal rolling contact.

2.  Grease Fill:

John Deere ensures that grease fill in each bearing is between 60% and 80%. 

The bearings purchased through the parts catalog company only had 30% fill and the distributor is currently selling bearings with only 35% fill.

Customer Impact: Grease is extremely important in maintaining the life of a bearing, especially in a sealed bearing such as this where the original amount of grease is all that will be available to protect the internal components.

3.  Radial Clearance:

Radial Clearance (RC) of the Non-OEM bearings is larger and possesses a wider range of variation than allowed by the John Deere specifications.

Customer Impact: Radial Clearance (RC) is the total clearance between the rings and the rolling elements and needs to be consistent for optimal load distribution and free rotation -- just enough to allow for thermal expansion. Too much or inconsistent RC, as found on the non-OEM bearings, can cause bearing failure.

4.  Raceway Roundness:

The John Deere inner ring and outer ring raceway roundness readings are acceptable.  The non-OEM bearings exhibited unsatisfactory readings as shown in the pictures below.

Customer Impact: Bearings with acceptable roundness readings like John Deere demonstrate a commitment to quality parts at the component level. Each component needs to be highly consistent to have a good working relationship with the neighboring parts. The non-OEM bearings are not consistent and are more likely to cause performance problems that would shorten the service life of the bearing.

5.  Seal Efficiency and

6.  Seal Integrity:

The non-OEM bearings were found to have undesirable seal issues. Randomly-selected samples were observed to have dented seals and strips of rubber were found in the internals of the bearings. This is detrimental in providing reliable sealing efficiency. In addition, the non-OEM bearings had light seal contact and seal torque which will not provide the protection of the John Deere bearings.

Customer Impact: Contamination due to poor sealing efficiency is one of the main causes of bearing failure. The non-OEM parts had seal problems that increase the risk for early contamination and shorter service life.

7.  Dynamic Radial Load Rating:

The bearings from the distributor were found to have dynamic radial load ratings 10% below the John Deere bearings. This is due to the non-OEM manufacturer utilizing a smaller ball size.

Customer Impact: The non-OEM bearings are using a smaller ball size to reduce manufacturing cost, and this puts the customer at risk for getting a bearing that will not stand up to the demanding conditions for which a John Deere OEM bearing is tested and approved.

8.  End Play:

End play is often a measured characteristic on double row ball bearings. The non-OEM bearings allow for up to 2.5 times more axial movement of the shaft than the John Deere product.

Customer Impact: The John Deere bearings provide a smaller, more consistent amount of end play. This is needed to ensure application compatibility. The non-OEM bearings are more likely to experience problems due to too much end play that could cause poor fit.

9.  Component Design:

Note the deeper grooves and special geometry on the John Deere part to keep a tight seal. Then note the shallow groove and looser fit used on the non-OEM bearings.

Customer Impact: A high-quality bearing needs to keep the dirt out. Seals are important, but so is the overall design of how all of the components fit together. Attention to detail makes a difference!

10.  Overall Quality:

Based on 18 key elements that evaluated material, workmanship, quality, and design on 10 different bearings for each brand, an overall quality rating can be determined. The tests concluded that the John Deere bearings had an overall 99.5% success rating, while the parts distributor had an 86.6% success rating and the catalog company bearings had an 81.6% success rating.

Customer Impact: Don’t be fooled by non-OEM bearings that may look the same on the outside. It’s the inside that really counts, and clearly there is a difference. Trying to save a few dollars up front on a non-OEM bearing will increase the chance of having a bearing problem.

Non-OEM versions of the AN212132 bearing sold by the catalog company and distributor exhibit concerns when compared to the baseline John Deere product and the John Deere specifications.

·        Help your parts and service professionals become familiar with the key differences between John Deere and other brands of bearings

·        Help your customers make an informed decision about which bearings they purchase

·        Include a bearing quality segment if you host your own parts expo or spring/fall customer clinics