What a bearing cross reference does and why you need one
A cross reference is a list that tells you which bearings from other manufacturers will work in place of an SKF bearing. The SKF 12400 is a specific bearing model made by SKF, a Swedish manufacturer. When you need a replacement and SKF parts are unavailable, too expensive, or you prefer another brand, a cross reference shows you the equivalent part numbers from competitors like Timken, FAG, NSK, or NTN.
The reason cross references matter is that bearings are standardized by dimension and load rating, not by brand. A bearing that fits the same shaft diameter, outer diameter, and width as the SKF 12400 will physically install in the same space and carry the same load. The cross reference saves you from having to measure the bearing yourself or call a supplier to hunt for alternatives.
This guide explains how to find cross references for the SKF 12400, what information you need before you search, and what to watch for when you switch brands.
Key Takeaways
- The SKF 12400 is a deep groove ball bearing with specific dimensions that other manufacturers replicate under different part numbers.
- Cross references are available from bearing distributors, manufacturer spec sheets, and online bearing databases, though not all sources cover all brands.
- Before ordering a replacement, confirm the bearing type (deep groove ball, cylindrical roller, etc.) and check that the substitute meets your load and speed requirements.
- Some cross references list multiple equivalents because different manufacturers may have slightly different tolerances or sealing options for the same basic bearing.
The SKF 12400 specifications and why they matter
The SKF 12400 is a deep groove ball bearing, which is the most common bearing type in industrial and automotive use. Its dimensions are 20 mm bore (inner diameter), 52 mm outer diameter, and 15 mm width. These three measurements define what will physically fit in your equipment.
When you search for a cross reference, you are looking for bearings from other makers that have the same 20 × 52 × 15 mm dimensions. A bearing with different dimensions will not drop into the same housing without modification. The load rating and speed rating also matter — if your equipment runs at high speed or carries heavy loads, a substitute bearing must meet or exceed those specifications, or it will fail prematurely.
SKF publishes the full specifications for the 12400 in their bearing catalog, which you can request from an SKF distributor or find on SKF's website. Having the spec sheet in front of you when you search for alternatives ensures you do not accidentally order a bearing that looks similar but has different tolerances or sealing.
Where to find cross references for the SKF 12400
Bearing distributors are the fastest source. Companies like Anixter, Motion Industries, and Applied Industrial Technologies carry multiple brands and maintain cross reference databases. Call a distributor with the SKF 12400 part number and ask what equivalents they stock. They will tell you the Timken, FAG, NSK, and NTN part numbers in seconds, and they can also tell you price and delivery time.
Online bearing databases let you search without calling. Websites like BearingWorks, Bearing King, and some manufacturer sites have searchable cross reference tools. Type in SKF 12400 and the tool returns a list of equivalent part numbers. The accuracy varies by site — some are comprehensive, others cover only major brands. These databases are free to use but may not show current pricing or stock status.
Manufacturer spec sheets sometimes include cross references. NSK, Timken, and FAG occasionally publish cross reference documents that list SKF equivalents. These are less common than distributor databases but are reliable when available. You can request them directly from the manufacturer or ask a distributor to send you one.
Your equipment manual or the original bearing housing may already list alternatives. If the bearing came from a machine you own, the manual sometimes notes approved substitutes. The bearing itself may have a label or marking that includes cross reference information.
Common cross references for the SKF 12400
The following table shows typical equivalents you may encounter. These are based on standard bearing dimensions, but always confirm with a distributor before ordering, because manufacturers occasionally update part numbers or tolerances.
| Manufacturer | Part Number | Type |
|---|---|---|
| SKF | 12400 | Deep groove ball bearing |
| Timken | 6004 or 6004-2RS | Deep groove ball bearing |
| FAG (Schaeffler) | 6004 or 6004-2RSR | Deep groove ball bearing |
| NSK | 6004 or 6004-2RS | Deep groove ball bearing |
| NTN | 6004 or 6004-2RS | Deep groove ball bearing |
Notice that most manufacturers use the number 6004 for this size. That is because bearing size designations follow an ISO standard — the 6004 designation tells you the bore is 20 mm and the outer diameter is 52 mm, regardless of who makes it. The suffix (like 2RS, which means sealed on both sides) tells you about sealing or shielding options.
The SKF 12400 is an open bearing with no seals. If you substitute a 6004-2RS (sealed version), it will fit physically but will run cooler and last longer in dirty environments because the seals keep contamination out. However, sealed bearings generate slightly more friction and heat, so they are not suitable for very high-speed applications. Check your equipment's speed rating before switching to a sealed version.
What to verify before you order a replacement
Once you have a cross reference part number, do not order when ready. Confirm three things: the bearing type, the load rating, and the sealing option.
Bearing type: Make sure the substitute is also a deep groove ball bearing, not a cylindrical roller bearing or another type. The part number alone does not always tell you. A distributor can confirm this in seconds.
Load rating: The SKF 12400 has a dynamic load rating (C) and a static load rating (C0). These numbers tell you how much radial and axial load the bearing can handle. If your equipment is heavily loaded, a substitute must meet or exceed these ratings. Sealed bearings sometimes have slightly lower ratings than open bearings of the same size, so check the spec sheet.
Sealing option: Decide whether you need an open bearing (no seals), a shielded bearing (metal shields that do not touch the balls), or a sealed bearing (rubber seals that touch the balls). Open bearings run fastest and coolest. Sealed bearings last longer in dirty conditions but generate more friction. Your equipment manual usually specifies which type is correct.
Why cross references sometimes list multiple options
You may find that a cross reference lists three or four different part numbers for what looks like the same bearing. This happens because manufacturers have slightly different tolerances, sealing designs, or internal clearances. A Timken 6004 may have a different internal clearance than an NSK 6004, for example, which affects how the bearing fits on the shaft and in the housing.
In most cases, any of the listed options will work. But if your equipment is precision machinery, a high-speed spindle, or a critical process, the small differences matter. A distributor or the equipment manufacturer can tell you which substitute is closest to the original SKF 12400 in terms of fit and performance.
Some cross references also list obsolete part numbers or regional variants. If a part number appears in a cross reference but a distributor says it is no longer made, ask for the current equivalent. Bearing manufacturers update their catalogs regularly, and old part numbers sometimes get replaced with new ones that have the same dimensions but different designations.
Frequently Asked Questions
Can I use any bearing with the same dimensions as the SKF 12400?
Physically, yes — a bearing with 20 mm bore, 52 mm outer diameter, and 15 mm width will install in the same space. But you should also check the load rating and speed rating to make sure the substitute can handle your equipment's demands. A cheaper bearing with lower ratings may fail early.
What does the 2RS or 2Z suffix mean on a cross reference bearing?
2RS means sealed on both sides with rubber seals. 2Z means shielded on both sides with metal shields. Open bearings have no suffix. Seals reduce speed capability but improve durability in dirty environments. Shields allow higher speeds than seals but offer less protection.
Is the SKF 12400 the same as a 6004 bearing?
They have the same dimensions and are functionally equivalent, but they are not the same part number. SKF uses the 12400 designation; most other manufacturers call the same bearing a 6004. Cross references connect these different naming systems.
Where can I get a cross reference if my distributor does not have one?
Try a second distributor — larger ones maintain more comprehensive cross reference databases. You can also contact SKF directly and ask for the equivalent part numbers from competitors. Some bearing manufacturers publish cross reference charts on their websites.
What if the cross reference shows a bearing that is no longer made?
Ask a distributor for the current replacement. Bearing manufacturers discontinue old part numbers and introduce new ones regularly. A distributor can tell you which current part number is the direct substitute and whether there are any differences in performance or fit.