NJ348 bearing: complete specifications & equivalents
The NJ348 is a ISO 15 radial bearing sized 240 x 500 x 95 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 240 mm |
| Outer diameter D | 500 mm |
| Width B | 95 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1590 kN |
| Basic static load rating C0 | 1950 kN |
| Fatigue load limit Pu | 160 kN |
| Limiting speed (mechanical) | 1300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 91300 g |
| Manufacturer designation | NTN NJ348 |
| 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 & NJ300-series range
| Bore d | 9.449 in |
|---|---|
| Outer diameter D | 19.685 in |
| Width B | 3.74 in |
| ISO bore code | 48 |
| Radial section height (D−d)/2 | 130 mm |
| Smallest bore in NJ300-series | 17 mm |
| Largest outer diameter in NJ300-series | 580 mm |
| Width range across NJ300-series | 14–108 mm |
| Bore position in NJ300-series (smallest first) | 31 of 33 |
| Bore above smallest NJ300-series size | 223 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ348-MA | 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 NJ348 model number is decoded
NJ348 is the standard section of the NTN NJ300 dimension series for a 240 mm shaft — 1590 kN of basic dynamic capacity in a 91300 g, open bearing. On the NTN nameplate NJ states which ring carries the ribs, which determines whether NJ348 floats or locates; the numeric remainder is the ISO 15 series and 240 mm bore reference, not a fit or clearance instruction. NTN ships these bearings open with normal (CN) radial clearance and P0 tolerance as standard; precision classes and C3/C4 clearance are separate order suffixes, not part of NJ348. With the inner ring rotating, catalogue practice is a m6/n6 shaft seat and an H7/H6 housing; the outer ring must remain free to creep slightly axially in non-locating NJ arrangements. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NJ348 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
- wind-turbine gearbox planet and rotor shafts
- ship propulsion line shafts and reduction gears
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- cage distortion after a mounting blow carried through the roller set
- roller-end and raceway scoring from inadequate oil flow under heavy radial load
- fretting corrosion on a loose rotating shaft seat
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
Selection pitfalls — read before you substitute
- At 240 mm bore, oil-lubricated arrangements toward 1,500 r/min need positive flow and drain design; the 91300 g NJ348 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Open NJ348 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 240 mm contact.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 500 mm race brinells and releases as vibration within hours.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NJ348 skids at 1,300 r/min and fails by smearing long before L10 fatigue.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 500 mm race brinells and releases as vibration within hours.
- The 1590/1950 kN ratings, 160 kN Pu and 91300 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ348 (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 NJ348?
NJ348 is an NTN NJ single-row cylindrical roller bearing to ISO 15: 240 mm bore, 500 mm OD and 95 mm width (9.449 × 19.685 × 3.74 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1590 kN, C0 1950 kN, Pu 160 kN, grease limiting speed 1,300 r/min, oil 1,500 r/min, mass about 91300 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. NJ348 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. NJ348 is supplied in the standard open execution shown in the table.
Can NJ348 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 NJ348?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 310 mm, Ew 430 mm. The nominal bore/OD remain 240/500 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 1,300 r/min grease / 1,500 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.