29448 bearing: complete specifications & equivalents
The 29448 is a ISO 104 radial bearing sized 240 x 440 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 | 240 mm |
| Outer diameter D | 440 mm |
| Width B | 122 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 2680 kN |
| Basic static load rating C0 | 8700 kN |
| Fatigue load limit Pu | 530 kN |
| Limiting speed (mechanical) | 740 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 82600 g |
| Manufacturer designation | NTN 29448 |
| 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 | 9.449 in |
|---|---|
| Outer diameter D | 17.323 in |
| Width B | 4.803 in |
| ISO bore code | 48 |
| 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) | 20 of 46 |
| Bore above smallest 29400-series size | 180 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 29448-E | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 240×440×122 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 29448 model number is decoded
29448 is the 240 mm member of NTN's heavy-section 29400 spherical-thrust family: 440 mm over the housing washer, 122 mm tall. NTN builds the number from 294 is the dimension series (heavy-section 29400 spherical-thrust family); 48 encodes the 240 mm bore (bore code x 5). Catalogue mass is about 83 kg for the full washer-and-roller stack. Minimum axial load matters here too: at speed the rollers skid on a lightly loaded bearing, so check the catalogue minimum-load formula before downsizing the thrust spring. On vertical shafts, confirm the minimum axial load from the rotor weight plus any spring preload before the first run at speed.
Typical equipment & failure modes
Common applications
- vertical hydro and pump-turbine main thrust blocks
- heavy rolling-mill and forging-press thrust seats
- large marine propulsion thrust supports
- crane and excavator main slew bearings duty
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
- thermal distress when oil viscosity was chosen by habit instead of the operating-temperature calculation
- fatigue spalling on the shaft-washer raceway beginning at the high-stress inner end of the roller contact
Selection pitfalls — read before you substitute
- At 240 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 440 mm OD and tallest stack — confirm housing space and oil capacity before upgrading a 293 position.
- Oil-bath level is set for the cage, not the housing: too low starves the contact, too high churns heat at the 740 r/min end of the range.
- Oil is not optional at this rating: the 740 r/min figure assumes oil lubrication, and a grease conversion is a redesign, not a fill change.
- 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.
- The Ca 2680/C0a 8700 kN ratings and 530 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 29448; 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 29448?
29448 is a spherical roller thrust bearing to ISO 104: 240 mm shaft-washer bore, 440 mm outside diameter, 122 mm stack height (9.449 x 17.323 x 4.803 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 2680 kN, C0a 8700 kN and a 530 kN fatigue load limit Pu; limiting speed 740 r/min with oil lubrication; mass about 82600 g.
How is the 29448 designation structured?
294 is the dimension series (heavy-section 29400 spherical-thrust family); 48 encodes the 240 mm bore (bore code x 5). The 440 mm OD and 122 mm height follow the ISO 104 boundary plan for that series.
Can 29448 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, 740 r/min, for 29448?
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 29448?
The 240/440/122 mm envelope is ISO 104 interchangeable, but roller profile, osculation, cage and washer details are maker-specific. Re-verify Ca 2680 kN / C0a 8700 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.