RNA4905 bearing: complete specifications & equivalents
The RNA4905 is a ISO 1206 radial bearing sized 30 x 42 x 17 mm (bore x OD x width). 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 | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 24.2 kN |
| Basic static load rating C0 | 34.5 kN |
| Fatigue load limit Pu | 4.15 kN |
| Reference speed (thermal) | 13000 rpm |
| Limiting speed (mechanical) | 15000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 61 g |
| Manufacturer designation | RNA 4905 |
| 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 |
|---|---|---|---|
| RNA4905-2RS | 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 (24.2/34.5 vs 21.6/27.5 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 model number is decoded
RNA 4905 is a ribbed machined-ring needle roller bearing (no inner ring) sized 30×42×17 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 30 mm shaft journal completes the bearing. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 30 mm under-roller diameter and the 17 mm width, with the 42 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 61 g at 30×42×17 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. 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
- 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
- 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
- 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.
- The quoted 24.2/34.5 kN ratings are SKF catalogue values for this exact execution (RNA 4905); 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 24.2/34.5 kN ratings and 61 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
Is the RNA 4905 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 have?
A RNA 4905 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 24.2 kN, static C0 34.5 kN, fatigue limit Pu 4.15 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 61 g.
What does RNA 4905 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.
Does the RNA 4905 need a hardened and ground shaft?
No. In this execution the 30 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.
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.