RNA4838 bearing: complete specifications & equivalents
The RNA4838 is a ISO 1206 radial bearing sized 210 x 240 x 50 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 210 mm |
| Outer diameter D | 240 mm |
| Width B | 50 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 220 kN |
| Basic static load rating C0 | 710 kN |
| Fatigue load limit Pu | 73.5 kN |
| Reference speed (thermal) | 1900 rpm |
| Limiting speed (mechanical) | 2200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3200 g |
| Manufacturer designation | RNA 4838 |
| 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-48-series range
| Bore d | 8.268 in |
|---|---|
| Outer diameter D | 9.449 in |
| Width B | 1.969 in |
| ISO bore code | 38 |
| Radial section height (D−d)/2 | 15 mm |
| Smallest bore in RNA-48-series | 120 mm |
| Largest outer diameter in RNA-48-series | 480 mm |
| Width range across RNA-48-series | 30–100 mm |
| Bore position in RNA-48-series (smallest first) | 9 of 19 |
| Bore above smallest RNA-48-series size | 90 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| RNA4838-XL | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 210×240×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| RNA4838 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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 RNA4838 model number is decoded
In SKF catalogue PUB BU/P1 17000, RNA 4838 designates a flanged, machined outer ring filled with needle rollers and a cage for a 210 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 210 mm Fw and 50 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. 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 3200 g at 210×240×50 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 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
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- hard-particle indentation in unfiltered lubricant
- rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away
Selection pitfalls — read before you substitute
- Above 50 mm bore, thermal growth matters: the 210 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.
- 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 220/710 kN ratings and 3200 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
How is the RNA 4838 designation read?
RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 210 mm and width 50 mm, OD 240 mm comes from the dimension series, and the flanged outer ring retains the caged rollers.
Can the RNA 4838 run on an unhardened shaft?
No. In this execution the 210 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 4838 be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 210 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 4838?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 210 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 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.