RNA4856 bearing: complete specifications & equivalents
The RNA4856 is a ISO 1206 radial bearing sized 305 x 350 x 69 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 305 mm |
| Outer diameter D | 350 mm |
| Width B | 69 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 429 kN |
| Basic static load rating C0 | 1320 kN |
| Fatigue load limit Pu | 129 kN |
| Reference speed (thermal) | 1300 rpm |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 9300 g |
| Manufacturer designation | RNA 4856 |
| 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 | 12.008 in |
|---|---|
| Outer diameter D | 13.78 in |
| Width B | 2.717 in |
| ISO bore code | 56 |
| Radial section height (D−d)/2 | 22.5 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) | 14 of 19 |
| Bore above smallest RNA-48-series size | 185 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| RNA4856-XL | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 305×350×69 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| RNA4856 | 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 RNA4856 model number is decoded
RNA 4856 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 305 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 305 mm Fw and 69 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 9300 g at 305×350×69 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. 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
- 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
- corrosion pitting from condensation in intermittently operated machinery
- 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 305 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.
- Hardness is load capacity: in families without an inner ring the 305 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 429/1320 kN ratings are SKF catalogue values for this exact execution (RNA 4856); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- The 429/1320 kN ratings and 9300 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
Can the RNA 4856 run on an unhardened shaft?
No. In this execution the 305 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 4856 be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 305 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 4856?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 305 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 22.5 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the RNA 4856?
A RNA 4856 measures 305 mm bore/Fw × 350 mm outside diameter × 69 mm width (12.008 × 13.78 × 2.717 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 429 kN, static C0 1320 kN, fatigue limit Pu 129 kN, limiting speed 1,400 r/min, reference speed 1,300 r/min, mass about 9300 g.
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.