RNA4904-2RS bearing: complete specifications & equivalents
The RNA4904-2RS is a ISO 1206 radial bearing sized 25 x 37 x 17 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 25 mm |
| Outer diameter D | 37 mm |
| Width B | 17 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 19.4 kN |
| Basic static load rating C0 | 22.4 kN |
| Fatigue load limit Pu | 2.65 kN |
| Limiting speed (mechanical) | 7500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 56 g |
| Manufacturer designation | RNA 4904.2RS |
| Standard | ISO 1206 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & RNA-49-series range
| Bore d | 0.984 in |
|---|---|
| Outer diameter D | 1.457 in |
| Width B | 0.669 in |
| ISO bore code | 04 |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in RNA-49-series | 14 mm |
| Largest outer diameter in RNA-49-series | 190 mm |
| Width range across RNA-49-series | 13–50 mm |
| Bore position in RNA-49-series (smallest first) | 5 of 28 |
| Bore above smallest RNA-49-series size | 11 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| RNA4904 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×37×17 mm envelope, but catalogue C/C0 differ between the executions (19.4/22.4 vs 21.6/28 kN) — boundary dimensions match, not a load-rating equivalent. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the RNA4904-2RS model number is decoded
RNA 4904.2RS belongs to the machined-ring needle roller family: an outer ring turned and ground to 37 mm with two retaining flanges, a roller-and-cage set inside, and envelope 25×37×17 mm on a hardened 25 mm shaft. Reading the designation: RNA gives the series and the numbers the boundary plan — 25 mm Fw for the shaft seat, 17 mm width; the 37 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 19.4/22.4 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.
Typical equipment & failure modes
Common applications
- guide rollers running on hardened tracks
- swing arms and lever pivots with oscillating duty
- cam followers built up from separate components
- crank pins and eccentrics where the hardened journal is the raceway
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- cage pocket wear and roller skew after sustained operation with too little radial preload
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- rolling-contact fatigue spalling after the rated L10 life
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- The quoted 19.4/22.4 kN ratings are SKF catalogue values for this exact execution (RNA 4904.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.
- The 19.4/22.4 kN ratings and 56 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Does the RNA 4904.2RS need a hardened and ground shaft?
No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead.
What mounting mistakes ruin a RNA 4904.2RS?
Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs.
Is the RNA 4904.2RS sealed?
No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty.
Which dimensions does the RNA 4904.2RS have?
A RNA 4904.2RS measures 25 mm bore/Fw × 37 mm outside diameter × 17 mm width (0.984 × 1.457 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19.4 kN, static C0 22.4 kN, fatigue limit Pu 2.65 kN, limiting speed 7,500 r/min, mass about 56 g.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring on 2026-09-26. Read our editorial & correction policy.