NJ312 bearing: complete specifications & equivalents
The NJ312 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 |
| Basic dynamic load rating C | 137 kN |
| Basic static load rating C0 | 126 kN |
| Fatigue load limit Pu | 15.4 kN |
| Limiting speed (mechanical) | 5500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1760 g |
| Manufacturer designation | NTN NJ312 |
| 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 | 12 |
| 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 |
|---|---|---|---|
| NJ312-ECP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 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 NJ312 model number is decoded
NTN lists NJ312 on the 60×130 mm envelope, 31 mm wide: a line-contact radial bearing with a pressed sheet-steel cage and a grease limiting speed of 5,500 r/min. The leading NJ defines the rib arrangement (inner ring two ribs + one outer rib); the dimension-series digits and the two-digit bore code resolve to 60 mm, with 130 mm OD and 31 mm width from the ISO 15 general plan. Line contact between rollers and raceways gives NJ312 high radial capacity but no tolerance for misalignment: beyond roughly 3–4 arc-minutes the roller ends edge-load and fatigue accelerates. With the inner ring rotating, catalogue practice is a k5/m5 shaft seat and an H7/H6 housing; the outer ring must remain free to creep slightly axially in non-locating NJ arrangements. 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
- cement and mining conveyor drive pulleys
- heavy industrial gearbox and reducer shafts
- large pump, turbine and compressor rotors
- rolling-mill auxiliary drive 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
- roller-end and raceway scoring from inadequate oil flow under heavy radial load
- fretting corrosion on a loose rotating shaft seat
- false brinelling on standby machines exposed to external vibration
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.
- Do not replace NJ312 with a deep-groove ball bearing on rating alone: line contact gives 137 kN radial capacity but the bearing cannot carry the thrust duty a ball bearing can and misalignment tolerance is only 3–4 arc-minutes.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 130 mm race brinells and releases as vibration within hours.
- Grease limiting speed 5,500 r/min and oil 6,500 r/min are different limits for NJ312: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- 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.
- The 137/126 kN ratings, 15.4 kN Pu and 1760 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ312 (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 NJ312?
NJ312 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 137 kN, C0 126 kN, Pu 15.4 kN, grease limiting speed 5,500 r/min, oil 6,500 r/min, mass about 1760 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. NJ312 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. NJ312 is listed among the ＊ ULTAGE-marked executions in 2203E.
Can NJ312 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 NJ312?
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 113 mm. The nominal bore/OD remain 60/130 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 5,500 r/min grease / 6,500 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.