NJ221 bearing: complete specifications & equivalents
The NJ221 is a ISO 15 radial bearing sized 105 x 190 x 36 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 | 190 mm |
| Width B | 36 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 223 kN |
| Basic static load rating C0 | 241 kN |
| Fatigue load limit Pu | 26.1 kN |
| Limiting speed (mechanical) | 3600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3870 g |
| Manufacturer designation | NTN NJ221 |
| 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 & NJ200-series range
| Bore d | 4.134 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 1.417 in |
| ISO bore code | 21 |
| Radial section height (D−d)/2 | 42.5 mm |
| Smallest bore in NJ200-series | 15 mm |
| Largest outer diameter in NJ200-series | 580 mm |
| Width range across NJ200-series | 11–92 mm |
| Bore position in NJ200-series (smallest first) | 20 of 36 |
| Bore above smallest NJ200-series size | 90 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ221-ECP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 105×190×36 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 NJ221 model number is decoded
NTN lists NJ221 on the 105×190 mm envelope, 36 mm wide: a line-contact radial bearing with a pressed sheet-steel cage and a grease limiting speed of 3,600 r/min. On the NTN nameplate NJ states which ring carries the ribs, which determines whether NJ221 floats or locates; the numeric remainder is the ISO 15 series and 105 mm bore reference, not a fit or clearance instruction. The 36 mm width and 42.5 mm section put the NJ200 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. The 2.1 kN-per-mm-bore figure (223 kN over 105 mm) lets a NJ221 interchange candidate be screened quickly against the same-envelope ball or roller alternatives. Heat the inner ring to max 120 °C for the 105 mm interference fit and support the ring face square during fitting; cocking over a keyway brinells the raceway before first rotation.
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
- 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
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- electrical pitting on VFD-driven motor shafts without grounding protection
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
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 190 mm raceway.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NJ221 skids at 3,600 r/min and fails by smearing long before L10 fatigue.
- Wide (22/23) and light (10/49) executions at 105 mm bore share bore but not OD/width; check the full NJ200 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 223/241 kN pair here belongs to NJ221 as printed, not to the bare size.
- Open NJ221 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 105 mm contact.
- The 223/241 kN ratings, 26.1 kN Pu and 3870 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ221 (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 NJ221?
NJ221 is an NTN NJ single-row cylindrical roller bearing to ISO 15: 105 mm bore, 190 mm OD and 36 mm width (4.134 × 7.48 × 1.417 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 223 kN, C0 241 kN, Pu 26.1 kN, grease limiting speed 3,600 r/min, oil 4,300 r/min, mass about 3870 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. NJ221 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. NJ221 is supplied in the standard open execution shown in the table.
Can NJ221 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 NJ221?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 126.8 mm, Ew 168.8 mm. The nominal bore/OD remain 105/190 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 3,600 r/min grease / 4,300 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.