NNC4948-CV bearing: complete specifications & equivalents
The NNC4948-CV is a ISO 15 radial bearing sized 240 x 320 x 80 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 | 320 mm |
| Width B | 80 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 781 kN |
| Basic static load rating C0 | 1760 kN |
| Fatigue load limit Pu | 173 kN |
| Reference speed (thermal) | 850 rpm |
| Limiting speed (mechanical) | 1100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 18500 g |
| Manufacturer designation | SKF NNC 4948 CV |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.4 double-row full complement cylindrical roller bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.4 double-row full complement cylindrical roller bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.4 double-row full complement cylindrical roller bearings); 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 & NNC4900-series range
| Bore d | 9.449 in |
|---|---|
| Outer diameter D | 12.598 in |
| Width B | 3.15 in |
| ISO bore code | 48 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in NNC4900-series | 60 mm |
| Largest outer diameter in NNC4900-series | 540 mm |
| Width range across NNC4900-series | 25–140 mm |
| Bore position in NNC4900-series (smallest first) | 17 of 25 |
| Bore above smallest NNC4900-series size | 180 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NNCF4948-CV | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 240×320×80 mm and equivalent catalogue ratings; the NNCF execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
| NNCL4948-CV | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 240×320×80 mm and equivalent catalogue ratings; the NNCL execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
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 NNC4948-CV model number is decoded
NNC4948-CV is the 240 mm bore entry in the NNC4900 range: a 240×320×80 mm double-row full-complement cylindrical roller bearing with a full complement of extra rollers fitted in place of a cage, rated C 781 kN / C0 1760 kN. The NNC configuration means a non-separable double-row full complement bearing with three integral inner-ring flanges and two retaining rings holding the outer ring on both sides; functionally the bearing is two-direction locating — the retaining-ring configuration closes both axial escape paths. Suffix CV identifies the full-complement execution: the space a cage would occupy is filled with extra rollers, trading speed for maximum radial capacity and stiffness. Selection arithmetic: C0/C ≈ 2.25 (1760 against 781 kN), and the Pu figure 173 kN is the fatigue load-limit floor for the SKF life equation; the catalogue lists 850 r/min thermal reference speed and 1,100 r/min mechanical limiting speed. Assembly note: check both retaining rings are seated in their grooves before installation; axial guidance in both directions makes this the locating pair member, so the mating bearing must float. Heat steel rings inductively to max 120 °C, and never wash a full-complement unit in a way that displaces rollers.
Typical equipment & failure modes
Common applications
- mining shovel and dragline pivots
- steelmaking and heavy crane sheaves
- large offshore winch and hook blocks
Known failure patterns
- inner-ring raceway spalling from overload or contamination in the line-contact hertz zone
- outer-ring raceway fatigue after extended service at loads above the catalogue L10 rating
- roller smearing between the uncaged rollers during slow skidding starts under heavy static load
- cage pocket wear from roller skidding at insufficient radial load or during start-up before oil film build-up
- surface distress (micro-pitting) when the EHL film falls below the composite roughness at high specific load
- uneven row loading from misalignment, concentrating fatigue on one row of the double complement
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- The NNCF/NNCL/NNC triplet shares the envelope and ratings but differs in outer-ring retention — one retaining ring, none, or two; selecting the wrong one changes the axial-locating scheme.
- Relubrication must reach both roller rows through the annular groove; blocked lube holes starve one row silently and show later as asymmetric raceway wear.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 320 mm raceway.
- Catalogue reference and limiting speeds are different criteria: observe the mechanical ceiling even when thermal calculations allow more.
- The 781/1760 kN ratings are SKF catalogue 17000 (2018) values for the CV execution; re-verify against the current catalogue for critical drives and keep the catalogue version with the specification.
Frequently asked questions
What are the dimensions and catalogue data of NNC4948-CV?
SKF NNC 4948 CV is a double-row full-complement cylindrical roller bearing with 240 mm bore, 320 mm OD and 80 mm width per ISO 15. SKF lists C 781 kN, C0 1760 kN, Pu 173 kN, reference speed 850 r/min and limiting speed 1,100 r/min, mass about 18500 g.
What does the NNC designation and CV suffix mean?
Suffix CV identifies the full-complement execution: the space a cage would occupy is filled with extra rollers, trading speed for maximum radial capacity and stiffness. Structurally this execution has a non-separable double-row full complement bearing with three integral inner-ring flanges and two retaining rings holding the outer ring on both sides.
Can NNC4948-CV take axial load and locate the shaft?
Yes, in both directions, because retaining rings close both sides of the outer ring; the paired bearing must then float.
How does NNC4948-CV compare with the other executions in the same envelope?
NNCF (one outer retaining ring, one-direction guidance), NNCL (no retaining ring, floating outer ring) and NNC (retaining rings both sides, two-direction location) share the ISO envelope and ratings but are not interchangeable in a locating arrangement.
What limits the service life of this bearing most often?
On full-complement bearings the dominant risks are roller smearing from skidding below minimum load and contamination; maintain minimum radial load, keep lubricant film thick and accelerate gently.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.4 double-row full complement cylindrical roller bearings on 2026-09-26. Read our editorial & correction policy.