NJ2304EA bearing: complete specifications & equivalents
The NJ2304EA is a ISO 15 radial bearing sized 20 x 52 x 21 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 20 mm |
| Outer diameter D | 52 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 49.5 kN |
| Basic static load rating C0 | 39 kN |
| Fatigue load limit Pu | 4.75 kN |
| Limiting speed (mechanical) | 12000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 212 g |
| Manufacturer designation | NTN NJ2304EA |
| 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 & NJ2300-series range
| Bore d | 0.787 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.827 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 16 mm |
| Smallest bore in NJ2300-series | 20 mm |
| Largest outer diameter in NJ2300-series | 580 mm |
| Width range across NJ2300-series | 21–175 mm |
| Bore position in NJ2300-series (smallest first) | 1 of 31 |
| Bore above smallest NJ2300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ2304EA | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the 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 NJ2304EA model number is decoded
NTN lists NJ2304EA on the 20×52 mm envelope, 21 mm wide: a line-contact radial bearing with the EA high-capacity pressed sheet-steel cage and a grease limiting speed of 12,000 r/min. On the NTN nameplate NJ states which ring carries the ribs, which determines whether NJ2304EA floats or locates; the numeric remainder is the ISO 15 series and 20 mm bore reference, not a fit or clearance instruction. The 21 mm width and 16.0 mm section put the NJ2300 series in the extra-wide (23) section; wide 22/23 variants at the same bore change OD, width and heat generation and are not drop-in swaps. Rating life at 49.5 kN C assumes clean oil and adequate film; the 4.75 kN Pu floor means contamination derating — not the C rating alone — governs adjusted life in dusty gearboxes. Mount the separable inner ring + roller assembly on the shaft first and slide the outer ring into the housing; never press the outer ring through the rollers of NJ2304EA.
Typical equipment & failure modes
Common applications
- appliance and office-machine drives
- agricultural PTO and implement gear shafts
- small conveyor and fan rotor positions
- small electric-motor armature shafts
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- rolling-contact fatigue after the catalogue L10 life is exceeded
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- Small 20 mm-bore cylindrical rollers are skid-sensitive: ensure the radial load exceeds the minimum-load floor at operating speed, or the NJ2304EA rollers smear even with correct grease.
- Wide (22/23) and light (10/49) executions at 20 mm bore share bore but not OD/width; check the full NJ2300 series code before substituting, because housing and shoulder geometry will not interchange.
- The 21 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 20 mm inner ring.
- Open NJ2304EA 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 20 mm contact.
- Open NJ2304EA 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 20 mm contact.
- The 49.5/39 kN ratings, 4.75 kN Pu and 212 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ2304EA (EA pressed-steel-cage 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 NJ2304EA?
NJ2304EA is an NTN NJ single-row cylindrical roller bearing to ISO 15: 20 mm bore, 52 mm OD and 21 mm width (0.787 × 2.047 × 0.827 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 49.5 kN, C0 39 kN, Pu 4.75 kN, grease limiting speed 12,000 r/min, oil 16,800 r/min, mass about 212 g. It is open, with the EA high-capacity 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. NJ2304EA 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. This page's bearing carries the EA pressed-steel-cage execution.
Can NJ2304EA 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 NJ2304EA?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 27.5 mm, Ew 45.5 mm. The nominal bore/OD remain 20/52 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 12,000 r/min grease / 16,800 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.