NU1044 bearing: complete specifications & equivalents
The NU1044 is a ISO 15 radial bearing sized 220 x 340 x 56 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 220 mm |
| Outer diameter D | 340 mm |
| Width B | 56 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 555 kN |
| Basic static load rating C0 | 750 kN |
| Fatigue load limit Pu | 67 kN |
| Limiting speed (mechanical) | 2000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 17900 g |
| Manufacturer designation | NTN NU1044 |
| 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 & NU1000-series range
| Bore d | 8.661 in |
|---|---|
| Outer diameter D | 13.386 in |
| Width B | 2.205 in |
| ISO bore code | 44 |
| Radial section height (D−d)/2 | 60 mm |
| Smallest bore in NU1000-series | 25 mm |
| Largest outer diameter in NU1000-series | 1090 mm |
| Width range across NU1000-series | 12–150 mm |
| Bore position in NU1000-series (smallest first) | 28 of 47 |
| Bore above smallest NU1000-series size | 195 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU1044-ML | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 220×340×56 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 NU1044 model number is decoded
NTN lists NU1044 on the 220×340 mm envelope, 56 mm wide: a line-contact radial bearing with a pressed sheet-steel cage and a grease limiting speed of 2,000 r/min. Reading the code: NU for the non-locating separable-inner-ring type, then the ISO 15 diameter/width series and the bore code — ×5 = 220 mm (00–03 use the 10/12/15/17 exception table). 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 NU1044. Equivalent-load planning treats NU1044 as a pure radial bearing: keep P below 555 kN at the required L10, and let a paired angular-contact or thrust part carry any sustained axial component. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NU1044 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- ship propulsion line shafts and reduction gears
- mining SAG/ball-mill drive shafts
- offshore drawworks and winch drums
- heavy press and large gearbox main 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
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- At 220 mm bore, oil-lubricated arrangements toward 2,300 r/min need positive flow and drain design; the 17900 g NU1044 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Wide (22/23) and light (10/49) executions at 220 mm bore share bore but not OD/width; check the full NU1000 series code before substituting, because housing and shoulder geometry will not interchange.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU1044 skids at 2,000 r/min and fails by smearing long before L10 fatigue.
- If the shaft must be located both ways, do not use NU1044 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 340 mm race brinells and releases as vibration within hours.
- The 555/750 kN ratings, 67 kN Pu and 17900 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU1044 (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 NU1044?
NU1044 is an NTN NU single-row cylindrical roller bearing to ISO 15: 220 mm bore, 340 mm OD and 56 mm width (8.661 × 13.386 × 2.205 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 555 kN, C0 750 kN, Pu 67 kN, grease limiting speed 2,000 r/min, oil 2,300 r/min, mass about 17900 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. NU1044 is two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially.
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. NU1044 is supplied in the standard open execution shown in the table.
Can NU1044 take axial load and locate a shaft?
the NU design carries no axial load and floats axially on both sides. Provide axial location with an adjacent locating bearing (angular-contact, deep-groove or a paired NJ/NUP set).
What do Fw and Ew mean for NU1044?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 250 mm, Ew 310 mm. The nominal bore/OD remain 220/340 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,000 r/min grease / 2,300 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.