51140 bearing: complete specifications & equivalents
The 51140 is a ISO 104 radial bearing sized 200 x 250 x 37 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 | 250 mm |
| Width B | 37 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 172 kN |
| Basic static load rating C0 | 675 kN |
| Fatigue load limit Pu | 20.4 kN |
| Limiting speed (mechanical) | 960 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3920 g |
| Manufacturer designation | NTN 51140 |
| 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 | 7.874 in |
|---|---|
| Outer diameter D | 9.843 in |
| Width B | 1.457 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 25 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) | 30 of 46 |
| Bore above smallest 51100-series size | 190 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 51140 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 51140 appears as a light-section 51100 thrust family bearing with a 200 mm shaft washer, a 250 mm housing diameter and 37 mm of stack height. Decoding 51140: 511 is the dimension series (light-section 51100 thrust family), with 40 encodes the 200 mm bore (bore code x 5). The static margin, C0a 675 kN against Ca 172 kN, is what carries slow oscillating or shock thrust without permanent raceway dents. Selection starts from the load direction: if thrust ever reverses, plan a second thrust bearing (or a double-direction execution) rather than relying on the unloaded raceway. 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
- 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
- rapid flaking after radial load was allowed onto the bearing — a single-direction thrust ball bearing carries axial load only
- lubricant starvation scoring on the raceway track when grease is thrown outward by centrifugal effect and never replaced
- washer face corrosion under long standstill in humid service, later printed into the raceway as evenly spaced pitting
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 511 light section is the speed-friendly end of the thrust-ball plan — for the same 200 mm bore it gives up load to gain OD, height and limiting-speed headroom.
- Do not reuse a thrust bearing to "absorb" shaft thermal growth — the bearing clamps axially, so growth must be handled on the radial-bearing side of the arrangement.
- Shock thrust above C0a 675 kN leaves dents that later become fatigue origins — crane-hook and press applications need the static check, not just the life calculation.
- Shock thrust above C0a 675 kN leaves dents that later become fatigue origins — crane-hook and press applications need the static check, not just the life calculation.
- The Ca 172/C0a 675 kN ratings and 20.4 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51140; 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 51140?
51140 is a single-direction thrust ball bearing to ISO 104: 200 mm shaft-washer bore, 250 mm outside diameter, 37 mm stack height (7.874 x 9.843 x 1.457 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 172 kN, C0a 675 kN and a 20.4 kN fatigue load limit Pu; the grease limiting speed is 960 r/min and the oil rating 1,400 r/min; mass about 3920 g.
How is the 51140 designation structured?
511 is the dimension series (light-section 51100 thrust family); 40 encodes the 200 mm bore (bore code x 5). The 250 mm OD and 37 mm height follow the ISO 104 boundary plan for that series.
Can 51140 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 51140?
At the 960 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 51140?
The 200/250/37 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 172 kN / C0a 675 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.