NA4856 bearing: complete specifications & equivalents
The NA4856 is a ISO 1206 radial bearing sized 280 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 | 280 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 | 15500 g |
| Manufacturer designation | NA 4856 |
| Standard | ISO 1206 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with 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. 7.4 machined rings with flanges, with 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 & NA-48-series range
| Bore d | 11.024 in |
|---|---|
| Outer diameter D | 13.78 in |
| Width B | 2.717 in |
| ISO bore code | 56 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in NA-48-series | 110 mm |
| Largest outer diameter in NA-48-series | 480 mm |
| Width range across NA-48-series | 30–100 mm |
| Bore position in NA-48-series (smallest first) | 14 of 19 |
| Bore above smallest NA-48-series size | 170 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NA4856 model number is decoded
For a 280 mm shaft that cannot be hardened on site, NA 4856 adds a hardened, ground inner ring to the machined needle roller design: envelope 280×350×69 mm per the dimension series 48 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 280 mm d and 69 mm B, the 350 mm outside diameter from the dimension series 48 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 429 kN against C0 1320 kN gives a C0/C ratio of 3.08, and the 129 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 69 mm width and s offset dimensions against the open execution before reusing an existing bore.
Typical equipment & failure modes
Common applications
- gearbox shafts where the journal cannot be hardened on site
- wheel and lever pivots needing a replaceable inner ring
- conveyor roller ends and return rollers
- agricultural implement pivots and cutter heads
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- 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
- hard-particle indentation in unfiltered lubricant
- inner-ring raceway spalling after the narrow ring section runs hot with excessive interference
Selection pitfalls — read before you substitute
- Above 50 mm bore, thermal growth matters: the 280 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.
- 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.
- Do not interchange envelope-identical needle families blindly: NA 4856 shares its 280×350×69 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- The 429/1320 kN ratings and 15500 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Which dimensions does the NA 4856 have?
A NA 4856 measures 280 mm bore/Fw × 350 mm outside diameter × 69 mm width (11.024 × 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 15500 g.
What does NA 4856 mean in SKF part numbering?
The letters mark a machined-ring needle roller bearing with inner ring: 280 mm bore, 69 mm width, 350 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Does the NA 4856 need a hardened and ground shaft?
Yes — that is the point of this family. The NA 4856 carries its own hardened, ground inner ring on a 280 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
What mounting mistakes ruin a NA 4856?
Mount the inner ring on the 280 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring on 2026-09-26. Read our editorial & correction policy.