NJ305EA bearing: complete specifications & equivalents
The NJ305EA is a ISO 15 radial bearing sized 25 x 62 x 17 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 25 mm |
| Outer diameter D | 62 mm |
| Width B | 17 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 49 kN |
| Basic static load rating C0 | 37.5 kN |
| Fatigue load limit Pu | 4.55 kN |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 242 g |
| Manufacturer designation | NTN NJ305EA |
| 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 | 0.984 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 0.669 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 18.5 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) | 3 of 33 |
| Bore above smallest NJ300-series size | 8 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ305EA | 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 NJ305EA model number is decoded
For pure radial duty on a 25 mm shaft NTN supplies NJ305EA: two integral ribs on the inner ring and one rib on the outer ring; the open execution is rated 11,000 r/min on grease and 15,600 r/min on oil. Reading the code: NJ for the one-direction-locating type, then the ISO 15 diameter/width series and the bore code — ×5 = 25 mm (00–03 use the 10/12/15/17 exception table). The 17 mm width and 18.5 mm section put the NJ300 series in the standard 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 kN C assumes clean oil and adequate film; the 4.55 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 NJ305EA.
Typical equipment & failure modes
Common applications
- small electric-motor armature shafts
- light gearbox layshaft and pinion positions
- two-wheeler and small-engine transmission shafts
- small pump and compressor rotor 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
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
Selection pitfalls — read before you substitute
- Small 25 mm-bore cylindrical rollers are skid-sensitive: ensure the radial load exceeds the minimum-load floor at operating speed, or the NJ305EA rollers smear even with correct grease.
- Wide (22/23) and light (10/49) executions at 25 mm bore share bore but not OD/width; check the full NJ300 series code before substituting, because housing and shoulder geometry will not interchange.
- Wide (22/23) and light (10/49) executions at 25 mm bore share bore but not OD/width; check the full NJ300 series code before substituting, because housing and shoulder geometry will not interchange.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 49/37.5 kN pair here belongs to NJ305EA as printed, not to the bare size.
- Open NJ305EA 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 25 mm contact.
- The 49/37.5 kN ratings, 4.55 kN Pu and 242 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ305EA (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 NJ305EA?
NJ305EA is an NTN NJ single-row cylindrical roller bearing to ISO 15: 25 mm bore, 62 mm OD and 17 mm width (0.984 × 2.441 × 0.669 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 49 kN, C0 37.5 kN, Pu 4.55 kN, grease limiting speed 11,000 r/min, oil 15,600 r/min, mass about 242 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. NJ305EA 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 NJ305EA 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 NJ305EA?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 34 mm, Ew 54 mm. The nominal bore/OD remain 25/62 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 11,000 r/min grease / 15,600 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.