29338 bearing: complete specifications & equivalents
The 29338 is a ISO 104 radial bearing sized 190 x 320 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 | 190 mm |
| Outer diameter D | 320 mm |
| Width B | 78 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1280 kN |
| Basic static load rating C0 | 4250 kN |
| Fatigue load limit Pu | 294 kN |
| Limiting speed (mechanical) | 1100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 26000 g |
| Manufacturer designation | NTN 29338 |
| 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 & 29300-series range
| Bore d | 7.48 in |
|---|---|
| Outer diameter D | 12.598 in |
| Width B | 3.071 in |
| ISO bore code | 38 |
| Radial section height (D−d)/2 | 65 mm |
| Smallest bore in 29300-series | 85 mm |
| Largest outer diameter in 29300-series | 1180 mm |
| Width range across 29300-series | 39–230 mm |
| Bore position in 29300-series (smallest first) | 12 of 31 |
| Bore above smallest 29300-series size | 105 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 29338-E | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 190×320×78 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 29338 model number is decoded
29338 is an NTN spherical roller thrust bearing of the medium-section 29300 spherical-thrust family: 190 mm bore, 320 mm outside diameter, 78 mm overall height in NTN Ball and Roller Bearings CAT.No.2203E. Decoding 29338: 293 is the dimension series (medium-section 29300 spherical-thrust family), with 38 encodes the 190 mm bore (bore code x 5). Shaft and housing washers separate, so the 190 mm shaft washer can be mounted on the shaft before the roller set and housing washer follow. Within the spherical-thrust plan, 292 is the light section and 294 the heavy one; stepping up from a 292 to a 294 at the same bore roughly doubles the C0a class. Check face runout of the support surfaces before assembly: the self-aligning feature absorbs steady misalignment, not a rocking seat.
Typical equipment & failure modes
Common applications
- heavy rolling-mill and forging-press thrust seats
- large marine propulsion thrust supports
- crane and excavator main slew bearings duty
- rotary kiln and furnace thrust positions
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
- flaking that started where radial load share grew past the design assumption — the bearing tolerates combined load only while axial load clearly dominates
- thermal distress when oil viscosity was chosen by habit instead of the operating-temperature calculation
- cage-pocket wear after long service with vibration at standstill, the rollers hammering the pocket surfaces
Selection pitfalls — read before you substitute
- At 190 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 293 medium section is the workhorse: balanced height and capacity for general heavy thrust duty at 190 mm bore.
- Self-aligning does not mean self-locating: the housing washer must stay free on its spherical seat — clamping it flat destroys the feature the 29338 was chosen for.
- Self-aligning does not mean self-locating: the housing washer must stay free on its spherical seat — clamping it flat destroys the feature the 29338 was chosen for.
- Self-aligning does not mean self-locating: the housing washer must stay free on its spherical seat — clamping it flat destroys the feature the 29338 was chosen for.
- The Ca 1280/C0a 4250 kN ratings and 294 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 29338; 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 29338?
29338 is a spherical roller thrust bearing to ISO 104: 190 mm shaft-washer bore, 320 mm outside diameter, 78 mm stack height (7.48 x 12.598 x 3.071 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 1280 kN, C0a 4250 kN and a 294 kN fatigue load limit Pu; limiting speed 1,100 r/min with oil lubrication; mass about 26000 g.
How is the 29338 designation structured?
293 is the dimension series (medium-section 29300 spherical-thrust family); 38 encodes the 190 mm bore (bore code x 5). The 320 mm OD and 78 mm height follow the ISO 104 boundary plan for that series.
Can 29338 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, 1,100 r/min, for 29338?
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 29338?
The 190/320/78 mm envelope is ISO 104 interchangeable, but roller profile, osculation, cage and washer details are maker-specific. Re-verify Ca 1280 kN / C0a 4250 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.