NN3088 bearing: complete specifications & equivalents
The NN3088 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 | 178000 g |
| Manufacturer designation | NTN NN3088 |
| 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 | 88 |
| 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 |
|---|---|---|---|
| NN3088 | 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 NN3088 model number is decoded
For pure radial duty on a 440 mm shaft NTN supplies NN3088: two integral ribs on the outer ring and a ribless, separable inner ring; the open execution is rated 800 r/min on grease and 940 r/min on oil. Digit by digit, NN3088 reads as NN (double row, ribbed inner ring, separable outer), ISO 15 series, and bore 440 mm; trailing letters such as EA or E mark the cage/capacity execution and are part of the order number. The separable ring comes off without removing the roller assembly from the other ring, which eases inspection and lets the non-locating arrangement accommodate thermal shaft growth. The 6.1 kN-per-mm-bore figure (2680 kN over 440 mm) lets a NN3088 interchange candidate be screened quickly against the same-envelope ball or roller alternatives. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NN3088 non-locating position preloads the bearing when the shaft grows.
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
- 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
- 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 178000 g NN3088 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Double-row NN precision bearings are typically ordered P5/P4 with specific radial clearance for spindle preloading; a P0/CN NN3088 does not substitute a precision-class execution.
- The 105.0 mm section at 440 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 157 mm-wide cavity.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 650 mm race brinells and releases as vibration within hours.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 2680/5100 kN pair here belongs to NN3088 as printed, not to the bare size.
- The 2680/5100 kN ratings, 370 kN Pu and 178000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN3088 (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 NN3088?
NN3088 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 178000 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. NN3088 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. NN3088 is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN3088?
NN3088 has a cylindrical bore and mounts on a plain machined shaft seat; a K execution (1:12 taper) exists in the NN3000 series when preload must be set by drive-up on a tapered seat.
What speeds and lubrication apply to NN3088?
NTN rates NN3088 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.