How do you cross-reference an industrial bearing?
Start with the complete bearing designation and manufacturer, then compare bearing type, boundary dimensions, internal design, clearance, seals or shields, cage, precision and operating requirements. The same basic number across two brands may indicate a similar size, but it does not automatically prove that every suffix and performance detail is equivalent.
That is the central rule of bearing cross-reference work: dimensions are the starting point, not the final approval.
This guide is for maintenance teams, distributors and equipment owners trying to replace SKF, FAG, NSK, NTN, KOYO, NACHI or other industrial bearings. It explains what information to collect before asking suppliers for an exact replacement or an approved alternative.
Separate the basic designation from the complete code
A bearing designation normally has a basic number plus optional prefixes and suffixes. The basic number often identifies the bearing family and size series. Additional characters may describe internal clearance, seals, shields, cage design, contact angle, tolerance class, lubrication features, matched arrangement or a manufacturer-specific variation.
Consider a common deep-groove ball bearing. The basic code `6004` is not the same purchase description as `6004-2Z`. The latter specifies metal shields on both sides in SKF nomenclature. An open bearing or a rubber-sealed version may share the same 20 x 42 x 12 mm boundary dimensions, but it is not the same configuration.
The same point becomes more important with specialized bearings:
- SKF 7307 BECBP is more specific than “7307 angular contact bearing.”
- SKF NU 306 ECM includes the NU arrangement and cage-related designation.
- FAG QJ219-N2-MPA includes details that should not disappear when requesting another brand.
- SKF 51226 is a thrust bearing arrangement, not a radial bearing selected only by bore size.
What must match in a bearing equivalent?
| Cross-reference field | Why it matters |
|---|---|
| Bearing type | Deep-groove, angular-contact, cylindrical-roller, spherical-roller and thrust bearings carry loads differently |
| Bore, outside diameter and width | Determines whether the bearing fits the shaft and housing envelope |
| Ring and shoulder design | Affects location, separability, axial movement and assembly |
| Internal clearance | Influences operating clearance after fit and temperature effects |
| Seals or shields | Changes contamination protection, friction and lubrication arrangement |
| Cage design and material | Can affect speed capability, temperature limits and application suitability |
| Contact angle or internal design | Important for axial capacity, preload and paired arrangements |
| Precision or tolerance class | Relevant to spindles, high-speed equipment and controlled running accuracy |
| Lubrication features | Grooves, holes, grease fill or special treatment may be part of the original design |
| Matched or special execution | A standard single bearing may not replace a paired, adjusted or application-specific set |
Why dimensions alone are not enough
Measuring bore, outside diameter and width is useful when the code is unreadable. These three dimensions can narrow the search, but many bearing variations share the same envelope.
A metal-shielded bearing, rubber-sealed bearing and open bearing may all fit the same housing. A normal-clearance bearing and a C3-clearance bearing may also share dimensions. They can behave differently after installation, especially when fits, speed, heat or contamination matter.
If the old bearing is available, collect:
- Clear photos of both ring faces and every visible marking.
- Box and label photos if original packaging remains.
- Bore, outside diameter and width.
- Bearing type and whether the rings separate.
- Seal or shield appearance.
- Machine make, model and bearing position.
- Shaft speed, load direction, temperature and contamination notes where known.
- Any old purchase record, parts manual or assembly drawing.
Bearing suffixes must be translated by function
Cross-reference tables are helpful, but suffixes should be translated into their engineering meaning before choosing another brand. For example, a suffix may indicate larger-than-normal clearance, a machined brass cage, metal shields, a lubrication groove or a particular contact angle. Another manufacturer may express the same feature with different letters, or may not offer a direct catalogue equivalent.
Use the current official catalogue or product data from each manufacturer. Do not build an RFQ from a screenshot of an old third-party table alone. Bearing designations and available variants can change, and some codes apply only to a product family.
A practical comparison table in the RFQ should look like this:
| Requirement | Original bearing | Proposed alternative |
|---|---|---|
| Manufacturer and full code | Record exactly | Supplier to state exactly |
| Bearing type | Confirm | Must match or explain difference |
| Dimensions | Bore x OD x width | Record actual catalogue dimensions |
| Clearance | Original suffix or measured requirement | State proposed class |
| Sealing | Open, shielded or sealed | State proposed execution |
| Cage | Original design | State proposed material and design |
| Precision | Original class where applicable | State proposed class |
| Speed and load data | Original catalogue/application basis | Provide comparison basis |
| Approval | Existing machine requirement | Buyer or bearing engineer approval |
A seven-step bearing cross-reference process
1. Record the original identification
Copy the complete code and brand. Photograph the marking before cleaning or handling removes more information.
2. Confirm the bearing family
Determine whether it is a radial ball bearing, angular-contact bearing, cylindrical or spherical roller bearing, thrust bearing, needle bearing or another type. Do not infer the family from bore size.
3. Confirm dimensions and interfaces
Check bore, outside diameter, width, shoulder geometry and any snap-ring groove, flange, tapered bore or adapter arrangement.
4. Decode the suffixes
List each known feature: clearance, cage, seals, precision, lubrication and matched arrangement. Use manufacturer documentation for the exact product family.
5. Compare operating requirements
If the original code is obsolete or unavailable, provide speed, radial and axial load direction, temperature, fit, lubrication and environment. The replacement may need application review rather than a simple code swap.
6. Request an explicit quotation
Ask the supplier to state whether the offer is the exact brand and code, a current successor, a dimensional match or a proposed functional alternative. These are different offers.
7. Approve before shipment
For a first order, check model markings, quantity, packaging and visible condition. Where authenticity matters, define the supply channel and brand verification route before payment. Photos alone cannot prove a branded bearing is genuine.
How to compare quotations from several bearing suppliers
The lowest number on a quotation may refer to a different scope. Compare one line at a time.
| Quotation item | What the supplier should state |
|---|---|
| Product | Manufacturer and complete designation |
| Supply type | Exact original, successor model or proposed alternative |
| Condition | New and unused; any storage or old-stock note where relevant |
| Quantity | Pieces, sets or pairs, stated clearly |
| Lead time | Stock availability or production lead time |
| Documents | Catalogue data, certificate or traceability documents included in the quoted scope |
| Packing | Original box, supplier packing, grouped carton and export packing |
| Commercial basis | Unit price, currency, trade term and quotation validity |
Exact replacement, successor or redesign?
An exact bearing can still be available from another source. An obsolete code may have a manufacturer-listed successor. A standard bearing with the same dimensions may be a candidate for review. In difficult cases, the machine assembly may need redesign.
These routes should not be presented as equal:
- **Exact replacement:** same manufacturer and complete designation.
- **Manufacturer successor:** officially replaced by a newer designation, subject to confirmation.
- **Cross-brand equivalent:** proposed matching product from another manufacturer.
- **Dimensional candidate:** fits the same envelope but needs technical comparison.
- **Application redesign:** bearing arrangement or surrounding parts change.
How MAVORIX supports bearing sourcing
MAVORIX helps overseas factories organize bearing lists, collect complete model information, compare China-side supplier quotations, coordinate label and visible-condition checks and consolidate approved bearings with other industrial spare parts. We do not claim to be an authorized distributor for every brand mentioned on this site.
Send the complete codes, preferred brands, accepted alternatives, quantities, machine information, urgency and destination. If a code is missing, include marking photos and dimensions. Our broader industrial bearing sourcing guide explains supplier and shipment considerations, while the contact page can be used to send a mixed bearing list.