51334 bearing: complete specifications & equivalents
The 51334 is a ISO 104 radial bearing sized 170 x 280 x 87 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 170 mm |
| Outer diameter D | 280 mm |
| Width B | 87 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 465 kN |
| Basic static load rating C0 | 1570 kN |
| Fatigue load limit Pu | 47.5 kN |
| Limiting speed (mechanical) | 590 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 21600 g |
| Manufacturer designation | NTN 51334 |
| 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 & 51300-series range
| Bore d | 6.693 in |
|---|---|
| Outer diameter D | 11.024 in |
| Width B | 3.425 in |
| ISO bore code | 34 |
| Radial section height (D−d)/2 | 55 mm |
| Smallest bore in 51300-series | 25 mm |
| Largest outer diameter in 51300-series | 340 mm |
| Width range across 51300-series | 18–110 mm |
| Bore position in 51300-series (smallest first) | 22 of 25 |
| Bore above smallest 51300-series size | 145 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51334-M | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 170×280×87 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 51334 model number is decoded
From the heavy-section 51300 thrust family, 51334 measures 170 mm through the shaft washer, 280 mm over the outside and 87 mm in assembled height. Decoding 51334: 513 is the dimension series (heavy-section 51300 thrust family), with 34 encodes the 170 mm bore (bore code x 5). The washer section here is 55.0 mm of radial height, and the catalogue couples it with Ca 465 kN / C0a 1570 kN. Choose the heavy-section 51300 thrust family when the shaft carries pure thrust in one direction at moderate speed — vertical shafts are the textbook case. The housing washer needs radial freedom in its seat so the bearing can centre itself; clamping it radially defeats the self-centring the loose fit is designed to give.
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
- 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
- edge loading from a shaft washer mounted off-centre, cutting the contact ellipse short at one side of the track
- 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 170 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 513 heavy section buys capacity with a larger 280 mm OD and taller stack — check the housing space before upgrading a 512 position to this series.
- 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.
- 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.
- The C0a of 1570 kN is a static rating: sizing continuous working thrust from C0a alone overstates what the raceway survives.
- The Ca 465/C0a 1570 kN ratings and 47.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51334; 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 51334?
51334 is a single-direction thrust ball bearing to ISO 104: 170 mm shaft-washer bore, 280 mm outside diameter, 87 mm stack height (6.693 x 11.024 x 3.425 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 465 kN, C0a 1570 kN and a 47.5 kN fatigue load limit Pu; the grease limiting speed is 590 r/min and the oil rating 840 r/min; mass about 21600 g.
How is the 51334 designation structured?
513 is the dimension series (heavy-section 51300 thrust family); 34 encodes the 170 mm bore (bore code x 5). The 280 mm OD and 87 mm height follow the ISO 104 boundary plan for that series.
Can 51334 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 51334?
At the 590 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 51334?
The 170/280/87 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 465 kN / C0a 1570 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.