51228-NTN bearing: complete specifications & equivalents
The 51228-NTN is a ISO 104 radial bearing sized 140 x 200 x 46 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 140 mm |
| Outer diameter D | 200 mm |
| Width B | 46 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 193 kN |
| Basic static load rating C0 | 595 kN |
| Fatigue load limit Pu | 20.6 kN |
| Limiting speed (mechanical) | 980 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4770 g |
| Manufacturer designation | NTN 51228 |
| 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 & 51200-series range
| Bore d | 5.512 in |
|---|---|
| Outer diameter D | 7.874 in |
| Width B | 1.811 in |
| ISO bore code | 28 |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 51200-series | 10 mm |
| Largest outer diameter in 51200-series | 520 mm |
| Width range across 51200-series | 11–112 mm |
| Bore position in 51200-series (smallest first) | 24 of 39 |
| Bore above smallest 51200-series size | 130 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 51228-NTN model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 51228 appears as a medium-section 51200 thrust family bearing with a 140 mm shaft washer, a 200 mm housing diameter and 46 mm of stack height. Decoding 51228: 512 is the dimension series (medium-section 51200 thrust family), with 28 encodes the 140 mm bore (bore code x 5). The static margin, C0a 595 kN against Ca 193 kN, is what carries slow oscillating or shock thrust without permanent raceway dents. If the duty is high speed with light thrust, check the minimum axial load formula first; a too-large thrust ball bearing fails by skid long before its Ca of 193 kN is ever approached. Mount the stack in order and confirm the shaft washer sits against its shoulder before loading: pressing through the balls brinells the raceway on the spot.
Typical equipment & failure modes
Common applications
- heavy press and mill screwdown thrust seats
- crane slew-ring auxiliary thrust positions
- large mixer and reactor vertical shafts
- bulk-handler stacker/reclaimer thrust pivots
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
- 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
- cage breakage after repeated shock reversal banged the ball set against the pocket bridges
- 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 140 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 512 medium section is the default choice: balanced height and capacity for general vertical-shaft duty at 140 mm bore.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51228 stack height of 46 mm and washer set differ from the double-direction execution.
- Radial load is the silent killer here: a belt pull or gear force on the same shaft must land on a radial bearing, because 51228 has no radial capacity at all.
- Shock thrust above C0a 595 kN leaves dents that later become fatigue origins — crane-hook and press applications need the static check, not just the life calculation.
- The Ca 193/C0a 595 kN ratings and 20.6 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51228; 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 51228?
51228 is a single-direction thrust ball bearing to ISO 104: 140 mm shaft-washer bore, 200 mm outside diameter, 46 mm stack height (5.512 x 7.874 x 1.811 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 193 kN, C0a 595 kN and a 20.6 kN fatigue load limit Pu; the grease limiting speed is 980 r/min and the oil rating 1,400 r/min; mass about 4770 g.
How is the 51228 designation structured?
512 is the dimension series (medium-section 51200 thrust family); 28 encodes the 140 mm bore (bore code x 5). The 200 mm OD and 46 mm height follow the ISO 104 boundary plan for that series.
Can 51228 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 51228?
At the 980 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 51228?
The 140/200/46 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 193 kN / C0a 595 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.