NJ234 bearing: complete specifications & equivalents
The NJ234 is a ISO 15 radial bearing sized 170 x 310 x 52 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 170 mm |
| Outer diameter D | 310 mm |
| Width B | 52 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 530 kN |
| Basic static load rating C0 | 635 kN |
| Fatigue load limit Pu | 59.5 kN |
| Limiting speed (mechanical) | 2200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 16700 g |
| Manufacturer designation | NTN NJ234 |
| 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 & NJ200-series range
| Bore d | 6.693 in |
|---|---|
| Outer diameter D | 12.205 in |
| Width B | 2.047 in |
| ISO bore code | 34 |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in NJ200-series | 15 mm |
| Largest outer diameter in NJ200-series | 580 mm |
| Width range across NJ200-series | 11–92 mm |
| Bore position in NJ200-series (smallest first) | 27 of 36 |
| Bore above smallest NJ200-series size | 155 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ234-ECML | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 170×310×52 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
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 NJ234 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, NJ234 appears as a 170 mm bore single-row cylindrical roller bearing (530 kN C / 635 kN C0) with a pressed sheet-steel cage, listed to the ISO 15 boundary plan. On the NTN nameplate NJ states which ring carries the ribs, which determines whether NJ234 floats or locates; the numeric remainder is the ISO 15 series and 170 mm bore reference, not a fit or clearance instruction. the bare number is the standard-capacity open execution with the normal pressed-steel cage; quote the full NJ234 designation when purchasing. The 170 mm (6.693 in) bore and 310 mm (12.205 in) OD are ISO 15 boundary values; fillet and shoulder dimensions must still come from the NTN mounting table for the 52 mm-wide ring. On NJ 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
- heavy press and large gearbox main shafts
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
- wind-turbine gearbox planet and rotor shafts
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
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- rolling-contact fatigue after the catalogue L10 life is exceeded
Selection pitfalls — read before you substitute
- At 170 mm bore, oil-lubricated arrangements toward 2,500 r/min need positive flow and drain design; the 16700 g NJ234 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The NJ rib arrangement is not interchangeable with another prefix on the same 170 mm seat: inner ring two ribs + one outer rib. Swapping NU for NJ changes axial location behaviour even though the 310×52 mm envelope matches.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NJ234 skids at 2,200 r/min and fails by smearing long before L10 fatigue.
- Open NJ234 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 170 mm contact.
- The 52 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 170 mm inner ring.
- The 530/635 kN ratings, 59.5 kN Pu and 16700 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ234 (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 NJ234?
NJ234 is an NTN NJ single-row cylindrical roller bearing to ISO 15: 170 mm bore, 310 mm OD and 52 mm width (6.693 × 12.205 × 2.047 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 530 kN, C0 635 kN, Pu 59.5 kN, grease limiting speed 2,200 r/min, oil 2,500 r/min, mass about 16700 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. NJ234 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. NJ234 is supplied in the standard open execution shown in the table.
Can NJ234 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 NJ234?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 208 mm, Ew 272 mm. The nominal bore/OD remain 170/310 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,200 r/min grease / 2,500 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.