Pitfalls when choosing bearings

By Bart van Oevelen - 2 Nov 2021

Pitfalls when choosing bearings

When choosing replacement bearings, mistake are easily made. Long type numbers, composite products… We would like to point out a few pitfalls and give some practical examples.

1. Seals

The first example of a common reading error: the markings on bearing seals. Bearings are available with various seal types. Each type has its own designation for identification purposes. That much is clear.

But what can lead to confusion, is the difference between bearings with single and double-sided seals. Double-sealed bearings are often identified by the number 2 before the seal designation on the inner or outer ring. The seal itself is also marked, but without the number 2.

For example, both seals on a 6200-2RS bearing are marked ‘RS’, not ‘2RS’. The same seals are used on bearings with single-sided seals. To avoid misunderstandings, always refer to the model number on the outer or inner ring of the bearing and not to the number on the seal itself.

Difference in format suffix between bearing and seal

2. Bearing housing with bearing

Type numbers of insert bearings for use in bearing housings are also frequently misread. Sometimes the number of the housing is used to order the bearing.

For example, a UCP204 bearing housing with bearing consists of a P204 housing and a UC204 bearing. Both parts have their own number. So the name UCP204, referring to the combination of both parts, is not on this product.

Do you need a replacement insert bearing? Then refer to the number engraved in the bearing itself, and forget about the bearing housing number.

Reference of complete assembly is not stated anywhere

3. Split bearing housings

Replacing parts of split bearing housings is also a precise job. There are many possible product combinations, and by no means all components are listed in the name of the unit.

To illustrate the above, ordering new parts for split bearing unit SNV120-F-L requires more info than this single reference. You also need a suitable bearing (e.g. 22311..-K), a clamping bush (H2311), an end cover (DKV120), seals (DH611) and two retaining rings (2x FRM120/4). This is just a specific example. The complete parts list depends on the desired configuration.

Whether you need a complete assembly, or just want to replace a single part, it’s not as easy as it seems. Our Account Managers will be happy to help you find the right products.

Split bearing housing with single components

4. Tapered roller bearings: loose outer and inner rings and sets

A tapered roller bearing (single or double row) consists of two detachable parts: a cup (outer ring) and a cone (inner ring with cage and roller assembly). Tapered roller bearings are available as a complete set, but cup and cone are also available separately. There are often multiple, similar type numbers available for both parts and sets.

Tapered roller bearing set LM11749/LM11710 made by Timken contains cone LM11749 and cup LM11710. So, this name clearly identifies both parts. The same set is also available as LM11749-99401, while cone LM11749 is also available as LM11749-20024. These alternative names do not always clearly indicate the composition of the product. Moreover, a “double” part number does not always refer to a complete tapered roller bearing.

Tip: fill in the article numbers of cone and cup with a slash in between them in the search bar on ABF.store to make sure that you end up with a complete set.

Complete tapered roller bearing set: cup and cone

5. Suffixes

Suffixes are used to indicate certain characteristics of a bearing. These abbreviations, which may refer to any specification, can easily cause doubt. For various reasons, manufacturers sometimes introduce new suffixes and suffix notations. Such name changes often relate to physical characteristics of products. These include material improvements, such as in FAG bearings of the C series. The predecessors of the C-variants can be safely replaced by these newer, quieter versions.

A suffix may also refer to a specification that makes the bearing suitable only for very specific applications. Punctuation marks in a type number may stand for huge differences. For example, it is not recommended to replace an NJ312-E-XL-M1A-QP51-C4 bearing with an NJ312-E-XL-M1A-C4. Although sizes and weights of both types are the same, the internal construction leads to very different product qualities.

Finally, a suffix does not always indicate a custom design. For example, the FAG notation >V indicates a “harmonized” design: there is absolutely no difference between the same bearings, it is just that they are manufactured at different locations. This indication appears only on the packaging, not on the bearings themselves.

Unsure about the meaning of a suffix? Each product page in the ABF Store has a handy suffix table with descriptions and an equivalence overview. They will show you which bearings are interchangeable without issue.

Suffix descriptions on ABF product page

Problems finding the correct bearing? Not sure which products you need? Please contact our Account Managers. They will be happy to help you select the right bearings and parts.

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Bart van Oevelen Product Manager baoe@abf.store +31 (0)165 722 011

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