NF221 bearing: complete specifications & equivalents
The NF221 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 NF221 |
| 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 & NF200-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 NF200-series | 20 mm |
| Largest outer diameter in NF200-series | 580 mm |
| Width range across NF200-series | 14–92 mm |
| Bore position in NF200-series (smallest first) | 18 of 34 |
| Bore above smallest NF200-series size | 85 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NF221 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 NF221 model number is decoded
NF221 is the standard section of the NTN NF200 dimension series for a 105 mm shaft — 223 kN of basic dynamic capacity in a 3870 g, open bearing. On the NTN nameplate NF states which ring carries the ribs, which determines whether NF221 floats or locates; the numeric remainder is the ISO 15 series and 105 mm bore reference, not a fit or clearance instruction. NTN prints two speed ceilings: 3,600 r/min grease and 4,300 r/min oil — the pressed-steel cage and lubricant film set the real limit at the 105 mm bore. Speed ratio check: limiting 3,600 r/min is .84 of the 4,300 r/min oil value for NF221; grease-churn heating closes that gap as fill quantity rises. On NF 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
- crusher and vibrating-screen drive shafts
- marine gearbox and deck-machinery shafts
- large electric-motor and generator rotors
- cement and mining conveyor drive pulleys
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
- hard-particle indentation of raceways in unfiltered oil or open arrangements
- 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.
- If the shaft must be located both ways, do not use NF221 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- 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 NF221 as printed, not to the bare size.
- The NF rib arrangement is not interchangeable with another prefix on the same 105 mm seat: one rib on each ring. Swapping NU for NJ changes axial location behaviour even though the 190×36 mm envelope matches.
- If the shaft must be located both ways, do not use NF221 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- The 223/241 kN ratings, 26.1 kN Pu and 3870 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NF221 (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 NF221?
NF221 is an NTN NF 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. NF221 is one integral rib on each ring — separable inner ring with single-direction axial guidance and a defined shaft position.
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. NF221 is supplied in the standard open execution shown in the table.
Can NF221 take axial load and locate a shaft?
the NF design gives one-direction axial guidance via its single outer-ring rib. The loose rib ring still only suits light/short-duration axial guidance; heavy thrust belongs to a dedicated thrust bearing.
What do Fw and Ew mean for NF221?
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.