NJ211 bearing: complete specifications & equivalents
The NJ211 is a ISO 15 radial bearing sized 55 x 100 x 21 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 55 mm |
| Outer diameter D | 100 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 64.5 kN |
| Basic static load rating C0 | 62.5 kN |
| Fatigue load limit Pu | 7.6 kN |
| Limiting speed (mechanical) | 6900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 626 g |
| Manufacturer designation | NTN NJ211 |
| 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 | 2.165 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 0.827 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 22.5 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) | 10 of 36 |
| Bore above smallest NJ200-series size | 40 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ211-ECP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×100×21 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 NJ211 model number is decoded
NJ211 belongs to the NTN cylindrical roller range in NTN Ball and Roller Bearings CAT.No.2203E, under the ＊ ULTAGE new-generation specification: line-contact rollers between ground raceways for a 64.5 kN dynamic rating in the 55 mm bore. 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 55 mm, with 100 mm OD and 21 mm width from the ISO 15 general plan. Minimum radial load matters: an unloaded NJ211 at high speed skids its rollers and smears the raceway; spring preload or the rotor weight typically covers the requirement in motors and pumps. Mass 626 g for the 55×100×21 mm NJ211 execution covers the pressed-steel cage and full roller complement; substitute on mass plus rating, not envelope alone. Keep the open bearing wrapped until fitting: the line-contact raceways of the 55 mm bore indent under a single hard particle, and the steel cage provides no sealing of its own.
Typical equipment & failure modes
Common applications
- papermaking and printing auxiliary drives
- fan and blower rotor positions
- industrial gearbox input and output shafts
- medium electric-motor and generator 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
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- false brinelling on standby machines exposed to external vibration
- brinelling from static overload or impact during handling
Selection pitfalls — read before you substitute
- On this 55 mm bore, shaft thermal growth can preload the inner ring if the fit is too tight; verify residual interference at temperature and confirm the float ring still slides after mounting NJ211.
- The NJ rib arrangement is not interchangeable with another prefix on the same 55 mm seat: inner ring two ribs + one outer rib. Swapping NU for NJ changes axial location behaviour even though the 100×21 mm envelope matches.
- If the shaft must be located both ways, do not use NJ211 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 100 mm race brinells and releases as vibration within hours.
- Do not replace NJ211 with a deep-groove ball bearing on rating alone: line contact gives 64.5 kN radial capacity but the bearing cannot carry the thrust duty a ball bearing can and misalignment tolerance is only 3–4 arc-minutes.
- The 64.5/62.5 kN ratings, 7.6 kN Pu and 626 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ211 (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 NJ211?
NJ211 is an NTN NJ single-row cylindrical roller bearing to ISO 15: 55 mm bore, 100 mm OD and 21 mm width (2.165 × 3.937 × 0.827 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 64.5 kN, C0 62.5 kN, Pu 7.6 kN, grease limiting speed 6,900 r/min, oil 8,200 r/min, mass about 626 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. NJ211 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. NJ211 is listed among the ＊ ULTAGE-marked executions in 2203E.
Can NJ211 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 NJ211?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 66.5 mm, Ew 88.5 mm. The nominal bore/OD remain 55/100 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 6,900 r/min grease / 8,200 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.