51156 bearing: complete specifications & equivalents
The 51156 is a ISO 104 radial bearing sized 280 x 350 x 53 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 280 mm |
| Outer diameter D | 350 mm |
| Width B | 53 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 305 kN |
| Basic static load rating C0 | 1270 kN |
| Fatigue load limit Pu | 32.5 kN |
| Limiting speed (mechanical) | 650 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 11800 g |
| Manufacturer designation | NTN 51156 |
| 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 & 51100-series range
| Bore d | 11.024 in |
|---|---|
| Outer diameter D | 13.78 in |
| Width B | 2.087 in |
| ISO bore code | 56 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 51100-series | 10 mm |
| Largest outer diameter in 51100-series | 640 mm |
| Width range across 51100-series | 9–85 mm |
| Bore position in 51100-series (smallest first) | 34 of 46 |
| Bore above smallest 51100-series size | 270 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 51156 model number is decoded
The light-section 51100 thrust family entry 51156 stacks a shaft washer, ball-and-cage set and housing washer into 53 mm of height over a 280 mm bore. Reading the code: 511 is the dimension series (light-section 51100 thrust family), and 56 encodes the 280 mm bore (bore code x 5). Flat-seat washers make the bearing tolerant of simple housings but demand square faces: the whole 305 kN rating assumes the load arrives truly axial. Choose the light-section 51100 thrust family when the shaft carries pure thrust in one direction at moderate speed — vertical shafts are the textbook case. After assembly, rotate under light load and check torque and temperature rise — a thrust ball bearing mounted with the washers swapped runs, but fails fast.
Typical equipment & failure modes
Common applications
- vertical hydro and pump-turbine thrust supports
- large marine winch and windlass shafts
- heavy press and mill screwdown thrust seats
- crane slew-ring auxiliary thrust positions
Known failure patterns
- cage pocket wear and ball skid polish after long running below the minimum axial load, the balls sliding instead of rolling on the washers
- housing-washer rocking on an out-of-square support face, seen as uneven wear around the raceway circle and rising running torque
- early fatigue from thrust reversal hammering the unloaded raceway, because the bearing has no contact surfaces for the opposite direction
- lubricant starvation scoring on the raceway track when grease is thrown outward by centrifugal effect and never replaced
- 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 280 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 511 light section is the speed-friendly end of the thrust-ball plan — for the same 280 mm bore it gives up load to gain OD, height and limiting-speed headroom.
- 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.
- Swapping the shaft and housing washers is an easy assembly error on the 280 mm size — the bores differ only slightly, but the wrong pairing walks off-centre under load.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51156 stack height of 53 mm and washer set differ from the double-direction execution.
- The Ca 305/C0a 1270 kN ratings and 32.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51156; 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 51156?
51156 is a single-direction thrust ball bearing to ISO 104: 280 mm shaft-washer bore, 350 mm outside diameter, 53 mm stack height (11.024 x 13.78 x 2.087 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 305 kN, C0a 1270 kN and a 32.5 kN fatigue load limit Pu; the grease limiting speed is 650 r/min and the oil rating 940 r/min; mass about 11800 g.
How is the 51156 designation structured?
511 is the dimension series (light-section 51100 thrust family); 56 encodes the 280 mm bore (bore code x 5). The 350 mm OD and 53 mm height follow the ISO 104 boundary plan for that series.
Can 51156 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 51156?
At the 650 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 51156?
The 280/350/53 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 305 kN / C0a 1270 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.