NJ312EA bearing: complete specifications & equivalents
The NJ312EA is a ISO 15 radial bearing sized 60 x 130 x 31 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 60 mm |
| Outer diameter D | 130 mm |
| Width B | 31 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 177 kN |
| Basic static load rating C0 | 157 kN |
| Fatigue load limit Pu | 19.1 kN |
| Limiting speed (mechanical) | 4900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1770 g |
| Manufacturer designation | NTN NJ312EA |
| 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 | 2.362 in |
|---|---|
| Outer diameter D | 5.118 in |
| Width B | 1.22 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 35 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) | 10 of 33 |
| Bore above smallest NJ300-series size | 43 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ312EA | 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 NJ312EA model number is decoded
NJ312EA is the standard section of the NTN NJ300 dimension series for a 60 mm shaft — 177 kN of basic dynamic capacity in a 1770 g, open bearing. On the NTN nameplate NJ states which ring carries the ribs, which determines whether NJ312EA floats or locates; the numeric remainder is the ISO 15 series and 60 mm bore reference, not a fit or clearance instruction. The 31 mm width and 35.0 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. Selection arithmetic: Pu 19.1 kN is the fatigue load limit feeding the adjusted-life equation, and the C0/C ratio of 0.89 (157/177 kN) shows the high-static-capacity proportioning of this 60 mm bore. 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 NJ312EA.
Typical equipment & failure modes
Common applications
- marine gearbox and deck-machinery shafts
- large electric-motor and generator rotors
- cement and mining conveyor drive pulleys
- heavy industrial gearbox and reducer 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
- brinelling from static overload or impact during handling
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- Induction-heat the 60 mm inner ring (max 120 °C) and mount it before fitting the outer ring; the ring mass makes square guidance essential — driving through the rollers brinells the 130 mm raceway.
- Grease limiting speed 4,900 r/min and oil 7,000 r/min are different limits for NJ312EA: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- The 35.0 mm section at 60 mm bore leaves a narrow oil path; with the EA pressed-steel-cage cage the relubrication groove and oil-level design must keep grease from churning in the 31 mm-wide cavity.
- Wide (22/23) and light (10/49) executions at 60 mm bore share bore but not OD/width; check the full NJ300 series code before substituting, because housing and shoulder geometry will not interchange.
- Open NJ312EA 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 60 mm contact.
- The 177/157 kN ratings, 19.1 kN Pu and 1770 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ312EA (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 NJ312EA?
NJ312EA is an NTN NJ single-row cylindrical roller bearing to ISO 15: 60 mm bore, 130 mm OD and 31 mm width (2.362 × 5.118 × 1.22 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 177 kN, C0 157 kN, Pu 19.1 kN, grease limiting speed 4,900 r/min, oil 7,000 r/min, mass about 1770 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. NJ312EA 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 NJ312EA 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 NJ312EA?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 77 mm, Ew 115 mm. The nominal bore/OD remain 60/130 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 4,900 r/min grease / 7,000 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.