RNA4905-2RS bearing: complete specifications & equivalents
The RNA4905-2RS is a ISO 1206 radial bearing sized 30 x 42 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 | 30 mm |
| Outer diameter D | 42 mm |
| Width B | 17 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 21.6 kN |
| Basic static load rating C0 | 27.5 kN |
| Fatigue load limit Pu | 3.25 kN |
| Limiting speed (mechanical) | 6300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 60 g |
| Manufacturer designation | RNA 4905.2RS |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 1.654 in |
| Width B | 0.669 in |
| ISO bore code | 05 |
| 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) | 7 of 28 |
| Bore above smallest RNA-49-series size | 16 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| RNA4905 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×42×17 mm envelope, but catalogue C/C0 differ between the executions (21.6/27.5 vs 24.2/34.5 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 RNA4905-2RS model number is decoded
SKF's dimension series 49 needle roller bearings without inner ring include RNA 4905.2RS: 30 mm Fw, 42 mm outside diameter, 17 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. Reading the designation: RNA gives the series and the numbers the boundary plan — 30 mm Fw for the shaft seat, 17 mm width; the 42 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. 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. Selection arithmetic: C 21.6 kN against C0 27.5 kN gives a C0/C ratio of 1.27, and the 3.25 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 42 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.
Typical equipment & failure modes
Common applications
- 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
- guide rollers running on hardened tracks
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- 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
- brinelling of raceways from impact or pressing force transmitted through the rolling elements
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.
- Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- Hardness is load capacity: in families without an inner ring the 30 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 21.6/27.5 kN ratings and 60 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What mounting mistakes ruin a RNA 4905.2RS?
Press on the ring faces only with a fitting sleeve, keep everything square to the 30 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 4905.2RS 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 4905.2RS have?
A RNA 4905.2RS measures 30 mm bore/Fw × 42 mm outside diameter × 17 mm width (1.181 × 1.654 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 21.6 kN, static C0 27.5 kN, fatigue limit Pu 3.25 kN, limiting speed 6,300 r/min, mass about 60 g.
What does RNA 4905.2RS mean in SKF part numbering?
RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 30 mm and width 17 mm, OD 42 mm comes from the dimension series, and the flanged outer ring retains the caged rollers.
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.