RNA6905 bearing: complete specifications & equivalents
The RNA6905 is a ISO 1206 radial bearing sized 30 x 42 x 30 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 | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 38 kN |
| Basic static load rating C0 | 62 kN |
| Fatigue load limit Pu | 7.65 kN |
| Reference speed (thermal) | 13000 rpm |
| Limiting speed (mechanical) | 15000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 110 g |
| Manufacturer designation | RNA 6905 |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 1.654 in |
| Width B | 1.181 in |
| ISO bore code | 05 |
| Radial section height (D−d)/2 | 6 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) | 6 of 22 |
| Bore above smallest RNA-69-series size | 14 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NX30-Z | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent. |
| NX30 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent. |
| NKX30-Z | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent. |
| NKX30 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent. |
| NKXR30 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent. |
| NKXR30-Z | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 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 RNA6905 model number is decoded
RNA 6905 belongs to the machined-ring needle roller family: an outer ring turned and ground to 42 mm with two retaining flanges, a roller-and-cage set inside, and envelope 30×42×30 mm on a hardened 30 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 30 mm Fw and 30 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. 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 38/62 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
- 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.
- Do not interchange envelope-identical needle families blindly: RNA 6905 shares its 30×42×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- Reference and limiting speeds are different limits: the 13,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- The 38/62 kN ratings and 110 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
How should the RNA 6905 be mounted?
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.
What limits the service life of a RNA 6905?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the RNA 6905?
A RNA 6905 measures 30 mm bore/Fw × 42 mm outside diameter × 30 mm width (1.181 × 1.654 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 38 kN, static C0 62 kN, fatigue limit Pu 7.65 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 110 g.
How is the RNA 6905 designation read?
RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 30 mm and width 30 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.