RNA6903 bearing: complete specifications & equivalents
The RNA6903 is a ISO 1206 radial bearing sized 22 x 30 x 23 mm (bore x OD x width). 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 | 23 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 18.7 kN |
| Basic static load rating C0 | 30.5 kN |
| Fatigue load limit Pu | 3.75 kN |
| Reference speed (thermal) | 18000 rpm |
| Limiting speed (mechanical) | 20000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 42 g |
| Manufacturer designation | RNA 6903 |
| 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-69-series range
| Bore d | 0.866 in |
|---|---|
| Outer diameter D | 1.181 in |
| Width B | 0.906 in |
| ISO bore code | 03 |
| Radial section height (D−d)/2 | 4 mm |
| Smallest bore in RNA-69-series | 16 mm |
| Largest outer diameter in RNA-69-series | 130 mm |
| Width range across RNA-69-series | 22–63 mm |
| Bore position in RNA-69-series (smallest first) | 3 of 22 |
| Bore above smallest RNA-69-series size | 6 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the RNA6903 model number is decoded
SKF's dimension series 69 needle roller bearings without inner ring include RNA 6903: 22 mm Fw, 30 mm outside diameter, 23 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The RNA 6903 code states Fw 22 and width 23 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. For life calculation, the 18.7/30.5 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
- 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
- corrosion pitting from condensation in intermittently operated machinery
- 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.
- Hardness is load capacity: in families without an inner ring the 22 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 18.7/30.5 kN ratings are SKF catalogue values for this exact execution (RNA 6903); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- The 18.7/30.5 kN ratings and 42 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
What are the dimensions and ratings of the RNA 6903?
A RNA 6903 measures 22 mm bore/Fw × 30 mm outside diameter × 23 mm width (0.866 × 1.181 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 18.7 kN, static C0 30.5 kN, fatigue limit Pu 3.75 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 42 g.
How is the RNA 6903 designation read?
RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 22 mm and width 23 mm, OD 30 mm comes from the dimension series, and the flanged outer ring retains the caged rollers.
Can the RNA 6903 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 6903 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.
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.