29444 bearing: complete specifications & equivalents
The 29444 is a ISO 104 radial bearing sized 220 x 420 x 122 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 | 420 mm |
| Width B | 122 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 2560 kN |
| Basic static load rating C0 | 8100 kN |
| Fatigue load limit Pu | 505 kN |
| Limiting speed (mechanical) | 760 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 77800 g |
| Manufacturer designation | NTN 29444 |
| Standard | ISO 104 |
| 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 & 29400-series range
| Bore d | 8.661 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 4.803 in |
| ISO bore code | 44 |
| Radial section height (D−d)/2 | 100 mm |
| Smallest bore in 29400-series | 60 mm |
| Largest outer diameter in 29400-series | 1770 mm |
| Width range across 29400-series | 42–426 mm |
| Bore position in 29400-series (smallest first) | 19 of 46 |
| Bore above smallest 29400-series size | 160 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 29444-E | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 220×420×122 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 29444 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 29444 appears as a heavy-section 29400 spherical-thrust family bearing with a 220 mm shaft washer, 420 mm across the housing washer and 122 mm of height. The designation is 294 is the dimension series (heavy-section 29400 spherical-thrust family) plus 44 encodes the 220 mm bore (bore code x 5). At 122 mm of height the bearing packs the heavy-section capacity into a stack far shorter than a comparable multi-row ball arrangement. If speed climbs toward the 760 r/min oil rating, the lubrication design — bath, circulation, cooling — becomes the real selection criterion. Torque the shaft nut against the shaft washer shoulder and verify axial clamping — a loose shaft washer frets the seat under 2560 kN class thrust.
Typical equipment & failure modes
Common applications
- heavy stacker/reclaimer and shiploading pivots
- vertical hydro and pump-turbine main thrust blocks
- heavy rolling-mill and forging-press thrust seats
- large marine propulsion thrust supports
Known failure patterns
- cage and roller-end scoring when the shaft was forced into alignment by the bearing itself during a bent-shaft rescue
- roller/raceway scuffing from an interrupted oil supply — at these loads the EHL film is the only thing between rolling and smearing
- roller skid smearing when axial load fell below the minimum while the shaft was still turning fast
- contamination denting from wear particles circulating in the oil bath — the dents seed the next round of surface fatigue
- contamination denting from wear particles circulating in the oil bath — the dents seed the next round of surface fatigue
Selection pitfalls — read before you substitute
- At 220 mm bore, seating geometry, oil supply and the minimum-load guarantee decide life — field improvisation on any of the three is the usual root cause.
- The 294 heavy section tops the plan at this bore with the largest 420 mm OD and tallest stack — confirm housing space and oil capacity before upgrading a 293 position.
- A spherical roller thrust bearing cannot take radial misalignment of the seats beyond its aligning travel — verify the housing geometry before blaming the bearing.
- The 122 mm stack height is part of the load path — any spacer or shim stack added under the housing washer must carry the full thrust without settling.
- Axial load must dominate; letting the radial share creep up because the radial bearing wore is the quiet path to early raceway flaking.
- The Ca 2560/C0a 8100 kN ratings and 505 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 29444; roller profile and osculation legitimately differ between manufacturers, so re-verify ratings, oil supply and minimum load before substituting another make.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 29444?
29444 is a spherical roller thrust bearing to ISO 104: 220 mm shaft-washer bore, 420 mm outside diameter, 122 mm stack height (8.661 x 16.535 x 4.803 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 2560 kN, C0a 8100 kN and a 505 kN fatigue load limit Pu; limiting speed 760 r/min with oil lubrication; mass about 77800 g.
How is the 29444 designation structured?
294 is the dimension series (heavy-section 29400 spherical-thrust family); 44 encodes the 220 mm bore (bore code x 5). The 420 mm OD and 122 mm height follow the ISO 104 boundary plan for that series.
Can 29444 handle misalignment and radial load?
Yes to both, with limits. The spherical housing-washer raceway lets the bearing self-align against steady seat misalignment, and the angled roller contact tolerates a radial share while axial load clearly dominates. It is not a radial bearing: shaft radial location still needs its own radial bearing.
Why does NTN print only an oil speed, 760 r/min, for 29444?
Spherical roller thrust bearings of this size work under contact stresses that need an elastohydrodynamic oil film; grease is reserved for the smallest, slowest duties. The printed figure is the limiting speed with the catalogue oil-lubrication state — bath level, viscosity and cooling decide how close a real installation may run.
What should be checked before substituting another make for 29444?
The 220/420/122 mm envelope is ISO 104 interchangeable, but roller profile, osculation, cage and washer details are maker-specific. Re-verify Ca 2560 kN / C0a 8100 kN, the oil speed rating and the minimum-load requirement against the donor catalogue before swapping on a rated drive.
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.