NN3088K bearing: complete specifications & equivalents
The NN3088K is a ISO 15 radial bearing sized 440 x 650 x 157 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 440 mm |
| Outer diameter D | 650 mm |
| Width B | 157 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 2680 kN |
| Basic static load rating C0 | 5100 kN |
| Fatigue load limit Pu | 370 kN |
| Limiting speed (mechanical) | 800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 172000 g |
| Manufacturer designation | NTN NN3088K |
| 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 | 17.323 in |
|---|---|
| Outer diameter D | 25.591 in |
| Width B | 6.181 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 105 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) | 39 of 40 |
| Bore above smallest NN3000-series size | 415 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN3088K | 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 NN3088K model number is decoded
NN3088K is an NTN NN cylindrical roller bearing: two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially, inside the 440×650×157 mm ISO 15 envelope. Numbering ties NN3088K to its envelope: type code NN, series NN3000, 440 mm bore; the 650×157 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. NTN prints two speed ceilings: 800 r/min grease and 940 r/min oil — the pressed-steel cage and lubricant film set the real limit at the 440 mm bore. Rating life at 2680 kN C assumes clean oil and adequate film; the 370 kN Pu floor means contamination derating — not the C rating alone — governs adjusted life in dusty gearboxes. 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
- coordinate-measuring and semiconductor-equipment drives
- machine-tool main spindles requiring high radial stiffness
- precision gearbox and indexing-drive shafts
- high-rpm motorised grinding and milling spindles
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- cage wear accelerated when the EA high-capacity roller complement runs continuously above its thermal balance
- roller-end and raceway scoring from inadequate oil flow under heavy radial load
- brinelling from static overload or impact during handling
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
Selection pitfalls — read before you substitute
- At 440 mm bore, oil-lubricated arrangements toward 940 r/min need positive flow and drain design; the 172000 g NN3088K ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The 157 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 440 mm inner ring.
- The NN rib arrangement is not interchangeable with another prefix on the same 440 mm seat: double row, ribbed inner ring, separable outer. Swapping NU for NJ changes axial location behaviour even though the 650×157 mm envelope matches.
- Open NN3088K units need application-supplied sealing and a defined lubricant schedule; film thickness is the first failure mode for line contact when viscosity drops at the 440 mm contact.
- The K tapered bore of NN3088K 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 2680/5100 kN ratings, 370 kN Pu and 172000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN3088K (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 NN3088K?
NN3088K is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 440 mm bore, 650 mm OD and 157 mm width (17.323 × 25.591 × 6.181 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 2680 kN, C0 5100 kN, Pu 370 kN, grease limiting speed 800 r/min, oil 940 r/min, mass about 172000 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. NN3088K 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. NN3088K is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN3088K?
The K suffix denotes a 1:12 tapered bore. NN3088K 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 NN3088 execution of the same envelope mounts on a plain seat.
What speeds and lubrication apply to NN3088K?
NTN rates NN3088K at 800 r/min with grease and 940 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.