1. Order code: 61904-2RS1
- Manufacturer: SKF
Quick summary
Type: SKF single row deep groove ball bearing — contact rubber seals on both sides
Dimensions: d 20 mm × D 37 mm × B 9 mm
Internal clearance: CN standard
Load ratings: basic dynamic C 6.37 kN · basic static C₀ 3.65 kN · fatigue load limit Pu 0.156 kN (Pu per the SKF General Catalogue)
Speed: limiting 12 000 r/min (SKF catalogue)
Cage: sheet steel — durable, good heat resistance
Axial load: Takes moderate axial load in both directions alongside radial load. Not for carrying high axial load
Lubrication: Greased for life at the SKF factory — enough for the whole bearing life, NO relubrication needed
Typical applications: Electric motors, fans, pumps, gearboxes, conveyors, agricultural machinery and industrial appliances
Supply: available stock in Vietnam with full invoice, Genuine SKF product and complete certificates
2. General information:
The single row deep groove ball bearing is the most widely used bearing type in industry. The deep raceway closely follows the balls, so the bearing carries radial load and axial load in both directions while friction stays very low, allowing high speed with little heat generation. The design is simple, non-separable and needs very little maintenance.
Designation 61904-2RS1 has a 20 mm bore, a 37 mm outside diameter, a 9 mm width, contact rubber seals on both sides and CN internal clearance.
3. Product overview
3.1 Dimensions
| Bore diameter | 20 mm |
| Outside diameter | 37 mm |
| Width | 9 mm |
3.2 Performance
| Basic dynamic load rating | 6.37 kN |
| Basic static load rating | 3.65 kN |
| Limiting speed | 12 000 r/min |
3.3 Properties
| Filling slot | None |
| Number of rows | 1 |
| Locating feature, outer ring | None |
| Bore type | Cylindrical |
| Cage type | Sheet steel |
| Matched arrangement | None |
| Radial internal clearance | CN |
| Bearing material | Steel |
| Coating | None |
| Sealing | seals on both sides |
| Seal type | Contact |
| Filling grease | Grease |
| Relubrication feature | None |
3.4 Logistics
| Net weight | 0.041 kg |
| eClass code | 23-05-08-01 |
| UNSPSC code | 31171504 |
4. Detailed technical data:
4.1 Basic dimensions
| Symbol | Value | Meaning |
| d | 20 mm | Bore diameter |
| D | 37 mm | Outside diameter |
| B | 9 mm | Width |
4.2 Calculation data
| Specification | Symbol | Value |
| Basic dynamic load rating | C | 6.37 kN |
| Basic static load rating | C0 | 3.65 kN |
| Fatigue load limit | Pu | 0.156 kN (Pu per the SKF General Catalogue) |
| Limiting speed | 12 000 r/min |
5. Reading the 61904-2RS1 designation and choosing the right variant
5.1 What 61904-2RS1 tells you
An SKF designation reads from left to right, with each group carrying one piece of information:
| Characters | Meaning |
| 6 | Single row deep groove ball bearing — a deep raceway carrying both radial load and axial load in both directions |
| 1 | Diameter series. For the same bore, the higher this figure the larger the bearing and the higher its load rating |
| 904 | Bore code. From 04 upwards, multiply by 5 to get the bore diameter; codes 00/01/02/03 correspond to 10/12/15/17 mm |
| 2RS1 | contact rubber seals on both sides |
In summary: an SKF single row deep groove ball bearing with a 20 mm bore, a 37 mm outside diameter, a 9 mm width and contact rubber seals on both sides.
5.2 Choosing the right sealing type for the environment
| Suffix | Sealing type | When to choose it |
| None | Open type | Clean environment, a separate lubrication system, or oil lubrication. You must grease it yourself when mounting |
| -2Z | Steel shields, with no contact against the inner ring | Moderately dusty environment. Friction stays low so high speed is retained. Greased as supplied |
| -2RS1 / -2RSH | Contact rubber seals on both sides | Heavy dust, damp and water splash. The best sealing, but friction is higher so the permissible speed drops noticeably |
| -2RSL | Low-friction rubber seals | When you need both sealing and low losses — a compromise between 2Z and 2RS1 |
| -2RZ | Non-contact seals | Better sealed than 2Z while keeping friction low |
Currently viewing: 61904-2RS1 — contact rubber seals on both sides. Greased at the SKF factory for the whole bearing life; no relubrication is needed and none can be added.
5.3 Internal clearance — the most commonly mis-selected item
| Clearance | Meaning | When to choose it |
| C2 | Smaller than standard | High positioning accuracy needed, light load, stable temperature |
| CN | Standard | Most ordinary applications: a loose or lightly interference fit, with a negligible temperature difference |
| C3 | Greater than standard | Both rings tightly fitted, or the inner ring more than 10 °C hotter than the outer ring — electric motors, fans, hot water pumps |
| C4 | Greater than C3 | Large temperature difference, very tight fits, or slight shaft misalignment |
This designation uses CN clearance. If your application makes the inner ring run significantly hotter than the outer ring, switch to the /C3 version.
5.4 Designations in the same 20 mm × 37 mm × 9 mm size distributed by DAVITA
| Designation | Sealing | Clearance |
| 61904 | open type, no seals and no shields | CN |
6. Typical applications and quick selection guide
The deep groove ball bearing is the most common type in industry: good radial load capacity, moderate axial load in both directions, and low friction that allows high speed.
- Electric motors and generators — light to moderate load, high speed, low noise required
- Industrial fans and blowers — light load, continuous running, rising temperature, so C3 clearance is usually used
- Water pumps and oil pumps — a sealed version is needed to keep moisture out
- Gearboxes, conveyors and rollers — supporting shafts where the load is not excessive
- Agricultural machinery and outdoor equipment — prefer the 2RS1 rubber-sealed version to keep out dust and water
6.1 Quick selection by operating condition
| Operating condition | Conclusion |
| Moderate radial load, high speed, clean environment | SUITABLE — this is the core operating range of the deep groove ball bearing |
| Very high radial load, low speed | CONSIDER CAREFULLY — move to a cylindrical roller bearing or a spherical roller bearing, which carry far higher radial load in the same size |
| High axial load with almost no radial load | NOT SUITABLE — use a thrust bearing or an angular contact ball bearing |
| Shaft misalignment, or housings that are not concentric | NOT SUITABLE — deep groove ball bearings tolerate misalignment very poorly. Use a self-aligning ball bearing or a spherical roller bearing |
| Inner ring more than 10 °C hotter than the outer ring | Choose the /C3 version instead of CN |
| Dirt, damp and water splash | Choose the -2RS1 or -2RSH version and accept the lower permissible speed |
| Moderate dust but high speed required | Choose the -2Z version |
7. Mounting and maintenance
7.1 Mounting
- Never strike the bearing directly. Pass the mounting force through the ring that is being press-fitted: on the shaft, press on the inner ring; in the housing, press on the outer ring. Striking the wrong ring leaves dents in the raceway
- Do not strike it directly with a hammer. Use a proper fitting sleeve or a bearing fitting tool kit
- Hot mounting with an induction heater for the larger sizes. Maximum 120 °C for rubber-sealed versions and 125 °C for open or 2Z versions. Do not use a blowtorch
- Check the shaft and housing bore tolerances before mounting. Too tight a fit removes the internal clearance and seizes the bearing once it heats up
- Deep groove ball bearings tolerate misalignment very poorly — check the concentricity of the two housings before running
7.2 Lubrication
- This designation is greased at the SKF factory from the outset, enough for the whole bearing life — no additional grease is needed
- Do not remove the seals or shields to add grease. Doing so destroys the seal and lets dirt inside
- When the grease reaches the end of its life, replace the whole bearing; that is how a sealed-for-life range is designed
7.3 Monitoring in operation
- A sudden rise in housing temperature usually signals overload, insufficient grease or too tight a fit
- A steady hum is normal; a gritty or squealing noise signals dirt ingress or spalling of the raceway
- Vibration that grows over time signals material fatigue — plan the replacement before it fails suddenly
- The bearing needs a minimum radial load. Running unloaded at high speed for long periods makes the balls skid on the raceway
8. Equivalent designations from other manufacturers
Basic number 61904 follow the ISO standard, so every maker shares them — the same bore, outside diameter and width. Only the suffixes for sealing type and clearance are written differently by each maker:
| Item | SKF | How other makers usually write it |
| Steel shields on both sides | -2Z | ZZ, 2Z, -2Z |
| Contact rubber seals on both sides | -2RS1 or -2RSH | 2RS, DDU, VV, 2RSR |
| Clearance greater than standard | /C3 | C3, CM |
| Polyamide cage | TN9 | TVH, TVP, J |
Note: an equivalent designation is a cross-reference on mounting dimensions only. Load ratings, noise level, the grease supplied and service life differ between makers — check them against your actual operating conditions before substituting. For an exact cross-reference, contact the DAVITA technical team for assistance.
9. Buying from DAVITA
| Item | Details |
| Availability | In stock in Ho Chi Minh City. Call the hotline for the quantity available at the time you need it |
| Commitment | Authorised SKF distributor in Vietnam — 100% genuine products |
| Documents | VAT invoice, genuine goods with complete certificates |
| Technical support | Advice on clearance and sealing selection, cross-reference to other makers, mounting and lubrication guidance |
| Delivery | Fast delivery within Ho Chi Minh City, courier shipping to all provinces |
9.1 Frequently asked questions
| Question | Answer |
| Can this bearing take axial load? | Yes, moderately and in both directions, alongside radial load. The deep raceway lets axial force pass through the ball contact points. But if axial force is the main load, a thrust bearing or an angular contact ball bearing must be used. |
| How do CN and C3 differ, and which should I choose? | CN is the standard clearance and C3 is larger. Choose C3 when both rings are tightly fitted, or when the inner ring runs more than 10 °C hotter than the outer ring — common in electric motors, fans and pumps. Choose CN for cool applications with loose fits. The designation shown uses CN clearance. |
| Is the bearing already greased? | Yes. SKF greases it at the factory, enough for the whole bearing life; no relubrication is needed and the seals should not be removed to add grease. |
| Why is the limiting speed lower than the reference speed? | The reference speed is calculated for a theoretical thermal equilibrium. The limiting speed is the real mechanical limit of the design — cage, seals and centrifugal strength. Use the limiting speed as the reference point when selecting machinery. |
| Can I replace it with another maker's designation? | The mounting dimensions follow ISO, so it will fit. But machining accuracy, cage material, the grease supplied and service life are not the same between makers. DAVITA supplies and warrants genuine SKF products only. |
| How do I know the goods are genuine? | DAVITA is an Authorised SKF Distributor in Vietnam, issuing VAT invoices with genuine goods and complete certificates. A genuine SKF box carries a QR code and an anti-counterfeit label that can be checked instantly in the SKF Authenticate app. |
CONTACT US FOR TECHNICAL ADVICE OR THE BEST QUOTE FOR THE SKF 61904-2RS1 DEEP GROOVE BALL BEARING
DAVITA ENGINEERING JOINT STOCK COMPANY — SKF bearing distributor in Vietnam. 100% genuine products, stock available for the fastest delivery, VAT invoice and complete certificates.
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