51410A bearing: complete specifications & equivalents
The 51410A is a ISO 104 radial bearing sized 50 x 110 x 43 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 50 mm |
| Outer diameter D | 110 mm |
| Width B | 43 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 148 kN |
| Basic static load rating C0 | 283 kN |
| Fatigue load limit Pu | 12.8 kN |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1900 g |
| Manufacturer designation | NTN 51410A |
| 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 & 51400-series range
| Bore d | 1.969 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.693 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 51400-series | 25 mm |
| Largest outer diameter in 51400-series | 300 mm |
| Width range across 51400-series | 24–120 mm |
| Bore position in 51400-series (smallest first) | 6 of 20 |
| Bore above smallest 51400-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51410A | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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 51410A model number is decoded
51410A is an NTN single-direction thrust ball bearing of the extra-heavy 51400 thrust family: 50 mm bore, 110 mm outside diameter, 43 mm overall height in NTN Ball and Roller Bearings CAT.No.2203E. The designation is 514 is the dimension series (extra-heavy 51400 thrust family) plus 10 encodes the 50 mm bore (bore code x 5); the trailing A marks an internal-design revision of this dimension. With Ca 148 kN and C0a 283 kN, each mm of shaft bore carries about 2.96 kN of dynamic axial rating. Against a thrust roller bearing of the same 50 mm bore, this bearing is cheaper, quieter and happier at speed, but carries far less load per mm of section. On a vertical shaft, pack grease between the washers and plan a relubrication path — centrifugal effect drives grease outward and the track runs dry without it.
Typical equipment & failure modes
Common applications
- vertical motor and pump thrust shoes
- machine-tool tailstock and steady-rest screws
- medium crane hook blocks and slewing jibs
- extruder and mixer thrust housings
Known failure patterns
- ball and raceway smearing from gyroscopic spin when the bearing runs fast under too little axial load — the minimum-load rule exists exactly for this
- fretting between shaft washer and shaft when the seat is cut loose — the washer creeps, the centre line shifts and the balls start running off-track
- early fatigue from thrust reversal hammering the unloaded raceway, because the bearing has no contact surfaces for the opposite direction
- contamination pitting from particles settling on the horizontal housing washer — the classic failure of vertical-shaft grease-lubricated seats
- contamination pitting from particles settling on the horizontal housing washer — the classic failure of vertical-shaft grease-lubricated seats
Selection pitfalls — read before you substitute
- In this size class the frequent miss is washer identification: keep the catalogued shaft/housing washer pairing of the 50 mm size together from unpacking to assembly.
- The 514 extra-heavy section is the top of the thrust-ball plan at this bore; beyond it the catalogue moves to spherical roller thrust bearings.
- The C0a of 283 kN is a static rating: sizing continuous working thrust from C0a alone overstates what the raceway survives.
- Single-direction means exactly that: thrust on 51410A in the wrong direction separates the washers and drops the ball set — if reversal is possible even during coast-down, engineer against it.
- Grease in a horizontal-washer seat stays only if the housing is designed to hold it; open vertical arrangements need an oil bath or a grease-retaining cover.
- The Ca 148/C0a 283 kN ratings and 12.8 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51410A; raceway geometry legitimately differs between manufacturers, so re-verify ratings and washer identification before substituting another make.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 51410A?
51410A is a single-direction thrust ball bearing to ISO 104: 50 mm shaft-washer bore, 110 mm outside diameter, 43 mm stack height (1.969 x 4.331 x 1.693 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 148 kN, C0a 283 kN and a 12.8 kN fatigue load limit Pu; the grease limiting speed is 1,400 r/min and the oil rating 2,000 r/min; mass about 1900 g.
How is the 51410A designation structured?
514 is the dimension series (extra-heavy 51400 thrust family); 10 encodes the 50 mm bore (bore code x 5); the trailing A marks an internal-design revision of this dimension. The 110 mm OD and 43 mm height follow the ISO 104 boundary plan for that series.
Can 51410A carry radial load or reversing thrust?
No. The raceways contact the balls at 90 deg to the shaft, so the rating is purely axial and single-direction. Radial load must be carried by a separate radial bearing, and reversing thrust needs a second thrust bearing or a double-direction execution.
Why does NTN specify a minimum axial load for 51410A?
At the 1,400 r/min class speed, centrifugal and gyroscopic effects make an under-loaded ball set skid and smear instead of roll. The catalogue minimum-load formula gives the axial preload — from the machine weight, springs or a dead-weight — that keeps the contact rolling.
What should be checked before substituting another make for 51410A?
The 50/110/43 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 148 kN / C0a 283 kN, the speed figures and the shaft/housing washer identification against the donor catalogue.
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.