51226-NTN bearing: complete specifications & equivalents
The 51226-NTN is a ISO 104 radial bearing sized 130 x 190 x 45 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 130 mm |
| Outer diameter D | 190 mm |
| Width B | 45 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 191 kN |
| Basic static load rating C0 | 565 kN |
| Fatigue load limit Pu | 20.2 kN |
| Limiting speed (mechanical) | 1000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4220 g |
| Manufacturer designation | NTN 51226 |
| 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 | 5.118 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 1.772 in |
| ISO bore code | 26 |
| 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) | 23 of 39 |
| Bore above smallest 51200-series size | 120 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 51226-NTN model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 51226 appears as a medium-section 51200 thrust family bearing with a 130 mm shaft washer, a 190 mm housing diameter and 45 mm of stack height. NTN builds the number from 512 is the dimension series (medium-section 51200 thrust family); 26 encodes the 130 mm bore (bore code x 5). Flat-seat washers make the bearing tolerant of simple housings but demand square faces: the whole 191 kN rating assumes the load arrives truly axial. Against a thrust roller bearing of the same 130 mm bore, this bearing is cheaper, quieter and happier at speed, but carries far less load per mm of section. Keep the support faces square: a housing face out of perpendicular by a few hundredths over the 190 mm OD already tilts the raceway and concentrates the 565 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
- contamination pitting from particles settling on the horizontal housing washer — the classic failure of vertical-shaft grease-lubricated seats
- lubricant starvation scoring on the raceway track when grease is thrown outward by centrifugal effect and never replaced
Selection pitfalls — read before you substitute
- For a 130 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 130 mm bore.
- Single-direction means exactly that: thrust on 51226 in the wrong direction separates the washers and drops the ball set — if reversal is possible even during coast-down, engineer against it.
- A housing washer pressed tight in its seat cannot self-centre; the resulting eccentric running shows up as cage wear long before raceway fatigue.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51226 stack height of 45 mm and washer set differ from the double-direction execution.
- The Ca 191/C0a 565 kN ratings and 20.2 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51226; 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 51226?
51226 is a single-direction thrust ball bearing to ISO 104: 130 mm shaft-washer bore, 190 mm outside diameter, 45 mm stack height (5.118 x 7.48 x 1.772 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 191 kN, C0a 565 kN and a 20.2 kN fatigue load limit Pu; the grease limiting speed is 1,000 r/min and the oil rating 1,500 r/min; mass about 4220 g.
How is the 51226 designation structured?
512 is the dimension series (medium-section 51200 thrust family); 26 encodes the 130 mm bore (bore code x 5). The 190 mm OD and 45 mm height follow the ISO 104 boundary plan for that series.
Can 51226 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 51226?
At the 1,000 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 51226?
The 130/190/45 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 191 kN / C0a 565 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.