51176 bearing: complete specifications & equivalents
The 51176 is a ISO 104 radial bearing sized 380 x 460 x 65 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 380 mm |
| Outer diameter D | 460 mm |
| Width B | 65 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 380 kN |
| Basic static load rating C0 | 1910 kN |
| Fatigue load limit Pu | 42 kN |
| Limiting speed (mechanical) | 500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 22300 g |
| Manufacturer designation | NTN 51176 |
| 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 | 14.961 in |
|---|---|
| Outer diameter D | 18.11 in |
| Width B | 2.559 in |
| ISO bore code | 76 |
| Radial section height (D−d)/2 | 40 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) | 39 of 46 |
| Bore above smallest 51100-series size | 370 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 51176 model number is decoded
NTN 51176 belongs to the light-section 51100 thrust family of single-direction thrust ball bearings: 380 / 460 / 65 mm (shaft bore / OD / height). The designation is 511 is the dimension series (light-section 51100 thrust family) plus 76 encodes the 380 mm bore (bore code x 5). Because the contact points run at 90 deg to the shaft, none of the rating is available for radial load — not even incidentally. Against a thrust roller bearing of the same 380 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
- large marine winch and windlass shafts
- heavy press and mill screwdown thrust seats
- crane slew-ring auxiliary thrust positions
- large mixer and reactor vertical shafts
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
- rapid flaking after radial load was allowed onto the bearing — a single-direction thrust ball bearing carries axial load only
- cage breakage after repeated shock reversal banged the ball set against the pocket bridges
- 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
- For a 380 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 380 mm bore it gives up load to gain OD, height and limiting-speed headroom.
- Shock thrust above C0a 1910 kN leaves dents that later become fatigue origins — crane-hook and press applications need the static check, not just the life calculation.
- Below the minimum axial load the balls skid; the catalogue Ca of 380 kN never saves a bearing that is running too lightly loaded at 500 r/min.
- Single-direction means exactly that: thrust on 51176 in the wrong direction separates the washers and drops the ball set — if reversal is possible even during coast-down, engineer against it.
- The Ca 380/C0a 1910 kN ratings and 42 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51176; 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 51176?
51176 is a single-direction thrust ball bearing to ISO 104: 380 mm shaft-washer bore, 460 mm outside diameter, 65 mm stack height (14.961 x 18.11 x 2.559 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 380 kN, C0a 1910 kN and a 42 kN fatigue load limit Pu; the grease limiting speed is 500 r/min and the oil rating 710 r/min; mass about 22300 g.
How is the 51176 designation structured?
511 is the dimension series (light-section 51100 thrust family); 76 encodes the 380 mm bore (bore code x 5). The 460 mm OD and 65 mm height follow the ISO 104 boundary plan for that series.
Can 51176 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 51176?
At the 500 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 51176?
The 380/460/65 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 380 kN / C0a 1910 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.