51340 bearing: complete specifications & equivalents
The 51340 is a ISO 104 radial bearing sized 200 x 340 x 110 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 200 mm |
| Outer diameter D | 340 mm |
| Width B | 110 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 595 kN |
| Basic static load rating C0 | 2220 kN |
| Fatigue load limit Pu | 61 kN |
| Limiting speed (mechanical) | 470 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 41800 g |
| Manufacturer designation | NTN 51340 |
| 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 & 51300-series range
| Bore d | 7.874 in |
|---|---|
| Outer diameter D | 13.386 in |
| Width B | 4.331 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in 51300-series | 25 mm |
| Largest outer diameter in 51300-series | 340 mm |
| Width range across 51300-series | 18–110 mm |
| Bore position in 51300-series (smallest first) | 25 of 25 |
| Bore above smallest 51300-series size | 175 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51340-M | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 200×340×110 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 51340 model number is decoded
51340 is the 200 mm member of NTN's heavy-section 51300 thrust family: 340 mm across the washers, 110 mm tall. Reading the code: 513 is the dimension series (heavy-section 51300 thrust family), and 40 encodes the 200 mm bore (bore code x 5). At 110 mm of height the stack is compact for the 200 mm bore class, trading section height for the heavy-section load level. Choose the heavy-section 51300 thrust family when the shaft carries pure thrust in one direction at moderate speed — vertical shafts are the textbook case. Keep the support faces square: a housing face out of perpendicular by a few hundredths over the 340 mm OD already tilts the raceway and concentrates the 2220 kN static capacity on a few balls.
Typical equipment & failure modes
Common applications
- bulk-handler stacker/reclaimer thrust pivots
- heavy rotary furnace and kiln thrust points
- vertical hydro and pump-turbine thrust supports
- large marine winch and windlass shafts
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
- edge loading from a shaft washer mounted off-centre, cutting the contact ellipse short at one side of the track
- edge loading from a shaft washer mounted off-centre, cutting the contact ellipse short at one side of the track
Selection pitfalls — read before you substitute
- For a 200 mm bore thrust bearing, the seating surfaces and oil supply decide service life; at this size a field-improvised housing is the usual root cause behind "premature" failures.
- The 513 heavy section buys capacity with a larger 340 mm OD and taller stack — check the housing space before upgrading a 512 position to this series.
- 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.
- Radial load is the silent killer here: a belt pull or gear force on the same shaft must land on a radial bearing, because 51340 has no radial capacity at all.
- Below the minimum axial load the balls skid; the catalogue Ca of 595 kN never saves a bearing that is running too lightly loaded at 470 r/min.
- The Ca 595/C0a 2220 kN ratings and 61 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51340; 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 51340?
51340 is a single-direction thrust ball bearing to ISO 104: 200 mm shaft-washer bore, 340 mm outside diameter, 110 mm stack height (7.874 x 13.386 x 4.331 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 595 kN, C0a 2220 kN and a 61 kN fatigue load limit Pu; the grease limiting speed is 470 r/min and the oil rating 670 r/min; mass about 41800 g.
How is the 51340 designation structured?
513 is the dimension series (heavy-section 51300 thrust family); 40 encodes the 200 mm bore (bore code x 5). The 340 mm OD and 110 mm height follow the ISO 104 boundary plan for that series.
Can 51340 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 51340?
At the 470 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 51340?
The 200/340/110 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 595 kN / C0a 2220 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.