NN4930K bearing: complete specifications & equivalents
The NN4930K is a ISO 15 radial bearing sized 150 x 210 x 60 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 150 mm |
| Outer diameter D | 210 mm |
| Width B | 60 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 380 kN |
| Basic static load rating C0 | 690 kN |
| Fatigue load limit Pu | 70.5 kN |
| Limiting speed (mechanical) | 2800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5620 g |
| Manufacturer designation | NTN NN4930K |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & NN4900-series range
| Bore d | 5.906 in |
|---|---|
| Outer diameter D | 8.268 in |
| Width B | 2.362 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in NN4900-series | 100 mm |
| Largest outer diameter in NN4900-series | 440 mm |
| Width range across NN4900-series | 40–118 mm |
| Bore position in NN4900-series (smallest first) | 7 of 18 |
| Bore above smallest NN4900-series size | 50 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN4930K | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 NN4930K model number is decoded
NN4930K is the extra-light (10/49) section of the NTN NN4900 dimension series for a 150 mm shaft — 380 kN of basic dynamic capacity in a 5620 g, open bearing. Numbering ties NN4930K to its envelope: type code NN, series NN4900, 150 mm bore; the 210×60 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. Double-row NN precision cylindrical roller bearing: ribbed inner ring with a separable outer ring, two roller rows for high radial stiffness on machine-tool spindles; the K suffix is a 1:12 tapered bore — mounted on a tapered seat or adapter sleeve and driven up to a precise radial clearance/preload; precision classes P5/P4/P2 and clearance are ordered separately. Speed ratio check: limiting 2,800 r/min is .85 of the 3,300 r/min oil value for NN4930K; grease-churn heating closes that gap as fill quantity rises. Provide axial location with an adjacent locating bearing rather than expecting the float cylindrical set to hold thrust on the 150 mm shaft.
Typical equipment & failure modes
Common applications
- CNC lathe and machining-centre spindle radial sets
- precision rotary-table and dividing-head bearings
- high-speed turbine and turbo-blower rotor supports
- coordinate-measuring and semiconductor-equipment drives
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- electrical pitting on VFD-driven motor shafts without grounding protection
- rolling-contact fatigue after the catalogue L10 life is exceeded
Selection pitfalls — read before you substitute
- At 150 mm bore, oil-lubricated arrangements toward 3,300 r/min need positive flow and drain design; the 5620 g NN4930K ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The 30.0 mm section at 150 mm bore leaves a narrow oil path; with the standard cage the relubrication groove and oil-level design must keep grease from churning in the 60 mm-wide cavity.
- The K tapered bore of NN4930K is driven up to a measured clearance: skipping the drive-up procedure in favour of a normal press fit leaves the precision spindle set either preloaded hot or loose under load.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 380/690 kN pair here belongs to NN4930K as printed, not to the bare size.
- The 60 mm width and abutment faces must be square to the axis; a tilted spacer concentrates load across the roller set and shows as uneven raceway polish on the 150 mm inner ring.
- The 380/690 kN ratings, 70.5 kN Pu and 5620 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN4930K (standard execution); other makes sharing the ISO 15 envelope revise internal geometry without changing the order number, so keep the 2203E reference with the specification for critical drives.
Frequently asked questions
What are the dimensions and catalogue data of NN4930K?
NN4930K is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 150 mm bore, 210 mm OD and 60 mm width (5.906 × 8.268 × 2.362 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 380 kN, C0 690 kN, Pu 70.5 kN, grease limiting speed 2,800 r/min, oil 3,300 r/min, mass about 5620 g. It is open, with a machined or stamped steel cage per the precision execution.
What is the difference between NU, NJ, NUP, N and NF cylindrical roller bearings?
NN and NNU are double-row precision designs rather than single-row rib variants: NN has a ribbed inner ring and separable outer ring, NNU the reverse; both give high radial stiffness for spindles and are commonly ordered with P5/P4 precision and a K 1:12 tapered bore for preload setting. NN4930K is the NN execution.
What do the EA, E and ＊ suffixes mean on NTN cylindrical roller bearings?
EA is NTN's high-capacity design with a pressed sheet-steel cage and optimised roller complement in the same ISO 15 envelope; E marks the high-capacity design at the larger bores; the ＊ symbol printed before the code in the NTN catalogue marks the ULTAGE new-generation specification and is not typed as part of the order number. NN4930K is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN4930K?
The K suffix denotes a 1:12 tapered bore. NN4930K mounts on a tapered shaft seat or adapter sleeve and is driven up to a measured residual clearance or preload — this is how precision spindle bearings achieve stiffness without locknut guesswork; the cylindrical-bore NN4930 execution of the same envelope mounts on a plain seat.
What do Fw and Ew mean for NN4930K?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 168.5 mm, Ew 196.5159 mm. The nominal bore/OD remain 150/210 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,800 r/min grease / 3,300 r/min oil.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.