NJ408 bearing: complete specifications & equivalents
The NJ408 is a ISO 15 radial bearing sized 40 x 110 x 27 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 40 mm |
| Outer diameter D | 110 mm |
| Width B | 27 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 106 kN |
| Basic static load rating C0 | 89 kN |
| Fatigue load limit Pu | 10.9 kN |
| Limiting speed (mechanical) | 5700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1270 g |
| Manufacturer designation | NTN NJ408 |
| 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 & NJ400-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.063 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in NJ400-series | 25 mm |
| Largest outer diameter in NJ400-series | 280 mm |
| Width range across NJ400-series | 21–65 mm |
| Bore position in NJ400-series (smallest first) | 4 of 13 |
| Bore above smallest NJ400-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ408-M | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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 NJ408 model number is decoded
NJ408 is an NTN NJ cylindrical roller bearing: two integral ribs on the inner ring and one rib on the outer ring — it locates the shaft in one axial direction, inside the 40×110×27 mm ISO 15 envelope. Numbering ties NJ408 to its envelope: type code NJ, series NJ400, 40 mm bore; the 110×27 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. Line contact between rollers and raceways gives NJ408 high radial capacity but no tolerance for misalignment: beyond roughly 3–4 arc-minutes the roller ends edge-load and fatigue accelerates. The 2.6 kN-per-mm-bore figure (106 kN over 40 mm) lets a NJ408 interchange candidate be screened quickly against the same-envelope ball or roller alternatives. Housing and shaft fillets must clear the ring chamfers of NJ408; an oversized radius locks the ring on its face and tilts the 27 mm-wide seat.
Typical equipment & failure modes
Common applications
- medium electric-motor and generator shafts
- pump and compressor crankshafts and rotors
- machine-tool gearbox and spindle radial sets
- material-handling drum and wheel shafts
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- cage distortion after a mounting blow carried through the roller set
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- hard-particle indentation of raceways in unfiltered oil or open arrangements
Selection pitfalls — read before you substitute
- On this 40 mm bore, shaft thermal growth can preload the inner ring if the fit is too tight; verify residual interference at temperature and confirm the float ring still slides after mounting NJ408.
- Open NJ408 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 40 mm contact.
- Open NJ408 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 40 mm contact.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 110 mm race brinells and releases as vibration within hours.
- Wide (22/23) and light (10/49) executions at 40 mm bore share bore but not OD/width; check the full NJ400 series code before substituting, because housing and shoulder geometry will not interchange.
- The 106/89 kN ratings, 10.9 kN Pu and 1270 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ408 (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 NJ408?
NJ408 is an NTN NJ single-row cylindrical roller bearing to ISO 15: 40 mm bore, 110 mm OD and 27 mm width (1.575 × 4.331 × 1.063 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 106 kN, C0 89 kN, Pu 10.9 kN, grease limiting speed 5,700 r/min, oil 6,700 r/min, mass about 1270 g. It is open, with a pressed sheet-steel cage.
What is the difference between NU, NJ, NUP, N and NF cylindrical roller bearings?
The prefix states the rib arrangement: NU has two outer-ring ribs and a ribless inner ring (float, no axial load); NJ adds ribs for one-direction location; NUP adds a loose L-ring to locate both directions; N has two inner-ring ribs and a separable outer ring; NF has one rib per ring for one-direction guidance. NJ408 is two integral ribs on the inner ring and one rib on the outer ring — it locates the shaft in one axial direction.
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. NJ408 is supplied in the standard open execution shown in the table.
Can NJ408 take axial load and locate a shaft?
the NJ design accepts axial load in one direction and provides one-way shaft location. For two-direction location use an NUP execution or an NJ pair with loose rib rings.
What do Fw and Ew mean for NJ408?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 58 mm, Ew 92 mm. The nominal bore/OD remain 40/110 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 5,700 r/min grease / 6,700 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.