NN3040K bearing: complete specifications & equivalents
The NN3040K is a ISO 15 radial bearing sized 200 x 310 x 82 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 200 mm |
| Outer diameter D | 310 mm |
| Width B | 82 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 725 kN |
| Basic static load rating C0 | 1170 kN |
| Fatigue load limit Pu | 107 kN |
| Limiting speed (mechanical) | 1900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 20800 g |
| Manufacturer designation | NTN NN3040K |
| 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 & NN3000-series range
| Bore d | 7.874 in |
|---|---|
| Outer diameter D | 12.205 in |
| Width B | 3.228 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 55 mm |
| Smallest bore in NN3000-series | 25 mm |
| Largest outer diameter in NN3000-series | 680 mm |
| Width range across NN3000-series | 16–163 mm |
| Bore position in NN3000-series (smallest first) | 27 of 40 |
| Bore above smallest NN3000-series size | 175 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN3040K | 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 NN3040K model number is decoded
NN3040K is the standard section of the NTN NN3000 dimension series for a 200 mm shaft — 725 kN of basic dynamic capacity in a 20800 g, open bearing. Numbering ties NN3040K to its envelope: type code NN, series NN3000, 200 mm bore; the 310×82 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. The 55.0 mm radial section ((310−200)/2) frames the roller complement; capacity per millimetre of bore is about 3.6 kN/mm before application factors. Equivalent-load planning treats NN3040K as a pure radial bearing: keep P below 725 kN at the required L10, and let a paired angular-contact or thrust part carry any sustained axial component. On NN arrangements confirm which ring is separable before heating: forcing the ribbed ring off over the roller complement damages the cage and rib faces.
Typical equipment & failure modes
Common applications
- high-speed turbine and turbo-blower rotor supports
- coordinate-measuring and semiconductor-equipment drives
- machine-tool main spindles requiring high radial stiffness
- precision gearbox and indexing-drive shafts
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- cage wear accelerated when the EA high-capacity roller complement runs continuously above its thermal balance
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- hard-particle indentation of raceways in unfiltered oil or open arrangements
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- At 200 mm bore, oil-lubricated arrangements toward 2,300 r/min need positive flow and drain design; the 20800 g NN3040K ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The 82 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 200 mm inner ring.
- The NN rib arrangement is not interchangeable with another prefix on the same 200 mm seat: double row, ribbed inner ring, separable outer. Swapping NU for NJ changes axial location behaviour even though the 310×82 mm envelope matches.
- The 82 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 200 mm inner ring.
- The 55.0 mm section at 200 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 82 mm-wide cavity.
- The 725/1170 kN ratings, 107 kN Pu and 20800 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN3040K (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 NN3040K?
NN3040K is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 200 mm bore, 310 mm OD and 82 mm width (7.874 × 12.205 × 3.228 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 725 kN, C0 1170 kN, Pu 107 kN, grease limiting speed 1,900 r/min, oil 2,300 r/min, mass about 20800 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. NN3040K 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. NN3040K is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN3040K?
The K suffix denotes a 1:12 tapered bore. NN3040K 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 NN3040 execution of the same envelope mounts on a plain seat.
What speeds and lubrication apply to NN3040K?
NTN rates NN3040K at 1,900 r/min with grease and 2,300 r/min with oil. The grease figure is the cage/film mechanical ceiling; the oil figure assumes circulating or carefully supplied oil that removes heat from the line-contact zone.
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.