29424 bearing: complete specifications & equivalents
The 29424 is a ISO 104 radial bearing sized 120 x 250 x 78 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 120 mm |
| Outer diameter D | 250 mm |
| Width B | 78 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1080 kN |
| Basic static load rating C0 | 3050 kN |
| Fatigue load limit Pu | 212 kN |
| Limiting speed (mechanical) | 1300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 18600 g |
| Manufacturer designation | NTN 29424 |
| 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 | 4.724 in |
|---|---|
| Outer diameter D | 9.843 in |
| Width B | 3.071 in |
| ISO bore code | 24 |
| Radial section height (D−d)/2 | 65 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) | 10 of 46 |
| Bore above smallest 29400-series size | 60 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 29424-E | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 120×250×78 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 29424 model number is decoded
NTN 29424 belongs to the heavy-section 29400 spherical-thrust family of spherical roller thrust bearings: 120 / 250 / 78 mm (bore / OD / height). Reading the code: 294 is the dimension series (heavy-section 29400 spherical-thrust family), and 24 encodes the 120 mm bore (bore code x 5). The single printed speed, 1,300 r/min, is an oil-lubrication figure: the catalogue greases these bearings only for the smallest duties, and this size is rated for oil. Where the shaft also needs radial location, pair this bearing with a spherical roller or cylindrical radial bearing — the thrust bearing is not a radial guide. Fill the housing with the specified oil to the level that reaches the cage — these bearings are oil-bath or circulation machines, not grease machines.
Typical equipment & failure modes
Common applications
- rotary kiln and furnace thrust positions
- large vertical mill and crusher main shafts
- heavy stacker/reclaimer and shiploading pivots
- vertical hydro and pump-turbine main thrust blocks
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
- fretting on the shaft seat after the washer crept under reversing axial shock
- fretting on the shaft seat after the washer crept under reversing axial shock
Selection pitfalls — read before you substitute
- At 120 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 250 mm OD and tallest stack — confirm housing space and oil capacity before upgrading a 293 position.
- Do not let the self-aligning travel absorb a bent shaft: the bearing aligns to seats, not to a shaft that whips.
- A spherical roller thrust bearing cannot take radial misalignment of the seats beyond its aligning travel — verify the housing geometry before blaming the bearing.
- Oil-bath level is set for the cage, not the housing: too low starves the contact, too high churns heat at the 1,300 r/min end of the range.
- The Ca 1080/C0a 3050 kN ratings and 212 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 29424; 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 29424?
29424 is a spherical roller thrust bearing to ISO 104: 120 mm shaft-washer bore, 250 mm outside diameter, 78 mm stack height (4.724 x 9.843 x 3.071 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 1080 kN, C0a 3050 kN and a 212 kN fatigue load limit Pu; limiting speed 1,300 r/min with oil lubrication; mass about 18600 g.
How is the 29424 designation structured?
294 is the dimension series (heavy-section 29400 spherical-thrust family); 24 encodes the 120 mm bore (bore code x 5). The 250 mm OD and 78 mm height follow the ISO 104 boundary plan for that series.
Can 29424 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, 1,300 r/min, for 29424?
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 29424?
The 120/250/78 mm envelope is ISO 104 interchangeable, but roller profile, osculation, cage and washer details are maker-specific. Re-verify Ca 1080 kN / C0a 3050 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.