RNA4844 bearing: complete specifications & equivalents
The RNA4844 is a ISO 1206 radial bearing sized 240 x 270 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 | 240 mm |
| Outer diameter D | 270 mm |
| Width B | 50 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 238 kN |
| Basic static load rating C0 | 815 kN |
| Fatigue load limit Pu | 81.5 kN |
| Reference speed (thermal) | 1700 rpm |
| Limiting speed (mechanical) | 1900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3600 g |
| Manufacturer designation | RNA 4844 |
| 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 | 9.449 in |
|---|---|
| Outer diameter D | 10.63 in |
| Width B | 1.969 in |
| ISO bore code | 44 |
| 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) | 11 of 19 |
| Bore above smallest RNA-48-series size | 120 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| RNA4844-XL | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 240×270×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| RNA4844 | 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 RNA4844 model number is decoded
SKF's dimension series 48 needle roller bearings without inner ring include RNA 4844: 240 mm Fw, 270 mm outside diameter, 50 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 — 240 mm Fw for the shaft seat, 50 mm width; the 270 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. 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 3600 g at 240×270×50 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. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 270 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.
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
- false brinelling of standby equipment under external vibration
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- Above 50 mm bore, thermal growth matters: the 240 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.
- The quoted 238/815 kN ratings are SKF catalogue values for this exact execution (RNA 4844); 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 238/815 kN ratings and 3600 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
Does the RNA 4844 need a hardened and ground shaft?
No. In this execution the 240 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.
What mounting mistakes ruin a RNA 4844?
Press on the ring faces only with a fitting sleeve, keep everything square to the 240 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 4844 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 4844 have?
A RNA 4844 measures 240 mm bore/Fw × 270 mm outside diameter × 50 mm width (9.449 × 10.63 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 238 kN, static C0 815 kN, fatigue limit Pu 81.5 kN, limiting speed 1,900 r/min, reference speed 1,700 r/min, mass about 3600 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.