NJ1021 bearing: complete specifications & equivalents
The NJ1021 is a ISO 15 radial bearing sized 105 x 160 x 26 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 105 mm |
| Outer diameter D | 160 mm |
| Width B | 26 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 117 kN |
| Basic static load rating C0 | 142 kN |
| Fatigue load limit Pu | 16 kN |
| Limiting speed (mechanical) | 4300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1810 g |
| Manufacturer designation | NTN NJ1021 |
| 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 & NJ1000-series range
| Bore d | 4.134 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 1.024 in |
| ISO bore code | 21 |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in NJ1000-series | 25 mm |
| Largest outer diameter in NJ1000-series | 720 mm |
| Width range across NJ1000-series | 12–100 mm |
| Bore position in NJ1000-series (smallest first) | 17 of 42 |
| Bore above smallest NJ1000-series size | 80 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ1021 | 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 NJ1021 model number is decoded
For pure radial duty on a 105 mm shaft NTN supplies NJ1021: two integral ribs on the inner ring and one rib on the outer ring; the open execution is rated 4,300 r/min on grease and 5,100 r/min on oil. Digit by digit, NJ1021 reads as NJ (inner ring two ribs + one outer rib), ISO 15 series, and bore 105 mm; trailing letters such as EA or E mark the cage/capacity execution and are part of the order number. NTN ships these bearings open with normal (CN) radial clearance and P0 tolerance as standard; precision classes and C3/C4 clearance are separate order suffixes, not part of NJ1021. Rating life at 117 kN C assumes clean oil and adequate film; the 16 kN Pu floor means contamination derating — not the C rating alone — governs adjusted life in dusty gearboxes. The NJ design locates in one direction only: for two-direction location fit the matching loose rib ring (NUP execution) or pair the bearings back to back on the 105 mm shaft.
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 wear accelerated when the EA high-capacity roller complement runs continuously above its thermal balance
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- rolling-contact fatigue after the catalogue L10 life is exceeded
- electrical pitting on VFD-driven motor shafts without grounding protection
Selection pitfalls — read before you substitute
- Induction-heat the 105 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 160 mm raceway.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NJ1021 skids at 4,300 r/min and fails by smearing long before L10 fatigue.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 160 mm race brinells and releases as vibration within hours.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NJ1021 skids at 4,300 r/min and fails by smearing long before L10 fatigue.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 160 mm race brinells and releases as vibration within hours.
- The 117/142 kN ratings, 16 kN Pu and 1810 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ1021 (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 NJ1021?
NJ1021 is an NTN NJ single-row cylindrical roller bearing to ISO 15: 105 mm bore, 160 mm OD and 26 mm width (4.134 × 6.299 × 1.024 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 117 kN, C0 142 kN, Pu 16 kN, grease limiting speed 4,300 r/min, oil 5,100 r/min, mass about 1810 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. NJ1021 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. NJ1021 is supplied in the standard open execution shown in the table.
Can NJ1021 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 NJ1021?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 119.5 mm, Ew 145.5 mm. The nominal bore/OD remain 105/160 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 4,300 r/min grease / 5,100 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.