NN3044 bearing: complete specifications & equivalents
The NN3044 is a ISO 15 radial bearing sized 220 x 340 x 90 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 | 90 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 905 kN |
| Basic static load rating C0 | 1480 kN |
| Fatigue load limit Pu | 132 kN |
| Limiting speed (mechanical) | 1700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 29300 g |
| Manufacturer designation | NTN NN3044 |
| 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 & NN3000-series range
| Bore d | 8.661 in |
|---|---|
| Outer diameter D | 13.386 in |
| Width B | 3.543 in |
| ISO bore code | 44 |
| Radial section height (D−d)/2 | 60 mm |
| Smallest bore in NN3000-series | 25 mm |
| Largest outer diameter in NN3000-series | 680 mm |
| Width range across NN3000-series | 16–163 mm |
| Bore position in NN3000-series (smallest first) | 28 of 40 |
| Bore above smallest NN3000-series size | 195 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN3044 | 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 NN3044 model number is decoded
NTN lists NN3044 on the 220×340 mm envelope, 90 mm wide: a line-contact radial bearing with a machined or stamped steel cage per the precision execution and a grease limiting speed of 1,700 r/min. Reading the code: NN for the double-row precision 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). Double-row NN precision cylindrical roller bearing: ribbed inner ring with a separable outer ring, two roller rows for high radial stiffness on machine-tool spindles; precision classes P5/P4/P2 and clearance are ordered separately. The 220 mm (8.661 in) bore and 340 mm (13.386 in) OD are ISO 15 boundary values; fillet and shoulder dimensions must still come from the NTN mounting table for the 90 mm-wide ring. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NN3044 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- precision gearbox and indexing-drive shafts
- high-rpm motorised grinding and milling spindles
- CNC lathe and machining-centre spindle radial sets
- precision rotary-table and dividing-head bearings
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- 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
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
Selection pitfalls — read before you substitute
- At 220 mm bore, oil-lubricated arrangements toward 2,100 r/min need positive flow and drain design; the 29300 g NN3044 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 905/1480 kN pair here belongs to NN3044 as printed, not to the bare size.
- 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.
- 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 90 mm width and abutment faces must be square to the axis; a tilted spacer concentrates load across the roller set and shows as uneven raceway polish on the 220 mm inner ring.
- The 905/1480 kN ratings, 132 kN Pu and 29300 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN3044 (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 NN3044?
NN3044 is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 220 mm bore, 340 mm OD and 90 mm width (8.661 × 13.386 × 3.543 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 905 kN, C0 1480 kN, Pu 132 kN, grease limiting speed 1,700 r/min, oil 2,100 r/min, mass about 29300 g. It is open, with a machined or stamped steel cage per the precision execution.
What is the difference between NU, NJ, NUP, N and NF cylindrical roller bearings?
NN and NNU are double-row precision designs rather than single-row rib variants: NN has a ribbed inner ring and separable outer ring, NNU the reverse; both give high radial stiffness for spindles and are commonly ordered with P5/P4 precision and a K 1:12 tapered bore for preload setting. NN3044 is the NN execution.
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. NN3044 is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN3044?
NN3044 has a cylindrical bore and mounts on a plain machined shaft seat; a K execution (1:12 taper) exists in the NN3000 series when preload must be set by drive-up on a tapered seat.
What speeds and lubrication apply to NN3044?
NTN rates NN3044 at 1,700 r/min with grease and 2,100 r/min with oil. The grease figure is the cage/film mechanical ceiling; the oil figure assumes circulating or carefully supplied oil that removes heat from the line-contact zone.
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.