RNA4903-2RS bearing: complete specifications & equivalents
The RNA4903-2RS is a ISO 1206 radial bearing sized 22 x 30 x 13 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 | 22 mm |
| Outer diameter D | 30 mm |
| Width B | 13 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 9.52 kN |
| Basic static load rating C0 | 12.9 kN |
| Fatigue load limit Pu | 1.53 kN |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 23 g |
| Manufacturer designation | RNA 4903.2RS |
| 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 | 0.866 in |
|---|---|
| Outer diameter D | 1.181 in |
| Width B | 0.512 in |
| ISO bore code | 03 |
| Radial section height (D−d)/2 | 4 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) | 4 of 28 |
| Bore above smallest RNA-49-series size | 8 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| RNA4903 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 22×30×13 mm envelope, but catalogue C/C0 differ between the executions (9.52/12.9 vs 11.4/16.3 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 RNA4903-2RS model number is decoded
RNA 4903.2RS is a ribbed machined-ring needle roller bearing (no inner ring) sized 22×30×13 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 22 mm shaft journal completes the bearing. The RNA 4903.2RS code states Fw 22 and width 13 mm directly; because the family has no inner ring, the 22 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Catalogue mass 23 g at 22×30×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. 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
- cam followers built up from separate components
- crank pins and eccentrics where the hardened journal is the raceway
- gearbox planetary and idler gears on hardened pins
- piston-pin style pivots in hydraulic pumps
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
- On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- 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.
- Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.
- The 9.52/12.9 kN ratings and 23 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
How is the RNA 4903.2RS designation read?
RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 22 mm and width 13 mm, OD 30 mm comes from the dimension series, and the flanged outer ring retains the caged rollers.
Can the RNA 4903.2RS run on an unhardened shaft?
No. In this execution the 22 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 4903.2RS be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 22 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 4903.2RS?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 22 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
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.