RNA4909-2RS bearing: complete specifications & equivalents
The RNA4909-2RS is a ISO 1206 radial bearing sized 52 x 68 x 22 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 | 52 mm |
| Outer diameter D | 68 mm |
| Width B | 22 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 39.1 kN |
| Basic static load rating C0 | 64 kN |
| Fatigue load limit Pu | 7.8 kN |
| Limiting speed (mechanical) | 3800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 160 g |
| Manufacturer designation | RNA 4909.2RS |
| 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 | 2.047 in |
|---|---|
| Outer diameter D | 2.677 in |
| Width B | 0.866 in |
| ISO bore code | 09 |
| Radial section height (D−d)/2 | 8 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) | 13 of 28 |
| Bore above smallest RNA-49-series size | 38 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| RNA4909 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 52×68×22 mm envelope, but catalogue C/C0 differ between the executions (39.1/64 vs 45.7/78 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 RNA4909-2RS model number is decoded
RNA 4909.2RS is a ribbed machined-ring needle roller bearing (no inner ring) sized 52×68×22 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 52 mm shaft journal completes the bearing. The RNA 4909.2RS code states Fw 52 and width 22 mm directly; because the family has no inner ring, the 52 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 39.1/64 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. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.
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
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- polymer cage deformation when the local temperature exceeds the 120 °C sustained limit
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- hard-particle indentation in unfiltered lubricant
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- Above 50 mm bore, thermal growth matters: the 52 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.
- Hardness is load capacity: in families without an inner ring the 52 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.
- The quoted 39.1/64 kN ratings are SKF catalogue values for this exact execution (RNA 4909.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- The 39.1/64 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Can the RNA 4909.2RS run on an unhardened shaft?
No. In this execution the 52 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.
How should the RNA 4909.2RS be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 52 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.
What limits the service life of a RNA 4909.2RS?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 52 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the RNA 4909.2RS?
A RNA 4909.2RS measures 52 mm bore/Fw × 68 mm outside diameter × 22 mm width (2.047 × 2.677 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.1 kN, static C0 64 kN, fatigue limit Pu 7.8 kN, limiting speed 3,800 r/min, mass about 160 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.