51314 bearing: complete specifications & equivalents
The 51314 is a ISO 104 radial bearing sized 70 x 125 x 40 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 70 mm |
| Outer diameter D | 125 mm |
| Width B | 40 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 148 kN |
| Basic static load rating C0 | 340 kN |
| Fatigue load limit Pu | 15.3 kN |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2010 g |
| Manufacturer designation | NTN 51314 |
| 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 | 2.756 in |
|---|---|
| Outer diameter D | 4.921 in |
| Width B | 1.575 in |
| ISO bore code | 14 |
| Radial section height (D−d)/2 | 27.5 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) | 10 of 25 |
| Bore above smallest 51300-series size | 45 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51314-SKF | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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 51314 model number is decoded
51314 is an NTN single-direction thrust ball bearing of the heavy-section 51300 thrust family: 70 mm bore, 125 mm outside diameter, 40 mm overall height in NTN Ball and Roller Bearings CAT.No.2203E. NTN builds the number from 513 is the dimension series (heavy-section 51300 thrust family); 14 encodes the 70 mm bore (bore code x 5). Flat-seat washers make the bearing tolerant of simple housings but demand square faces: the whole 148 kN rating assumes the load arrives truly axial. The 70/125/40 envelope follows ISO 104, so dimensional interchange holds between makers — raceway osculation and ratings do not automatically follow. Keep the support faces square: a housing face out of perpendicular by a few hundredths over the 125 mm OD already tilts the raceway and concentrates the 340 kN static capacity on a few balls.
Typical equipment & failure modes
Common applications
- heavy press and forging-machine thrust seats
- ship winch and capstan thrust shafts
- crusher main-shaft thrust supports
- large rotary-table and index-table thrust rings
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
- lubricant starvation scoring on the raceway track when grease is thrown outward by centrifugal effect and never replaced
Selection pitfalls — read before you substitute
- At 70 mm bore the washers are heavy enough to sag out of square during assembly — support the stack horizontally where possible and verify face runout before loading.
- The 513 heavy section buys capacity with a larger 125 mm OD and taller stack — check the housing space before upgrading a 512 position to this series.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51314 stack height of 40 mm and washer set differ from the double-direction execution.
- The 1,400 r/min speed figure assumes the catalogue lubrication state; at high speed the limiting factor is often the minimum load, not the rating table.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51314 stack height of 40 mm and washer set differ from the double-direction execution.
- The Ca 148/C0a 340 kN ratings and 15.3 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51314; 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 51314?
51314 is a single-direction thrust ball bearing to ISO 104: 70 mm shaft-washer bore, 125 mm outside diameter, 40 mm stack height (2.756 x 4.921 x 1.575 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 148 kN, C0a 340 kN and a 15.3 kN fatigue load limit Pu; the grease limiting speed is 1,400 r/min and the oil rating 2,000 r/min; mass about 2010 g.
How is the 51314 designation structured?
513 is the dimension series (heavy-section 51300 thrust family); 14 encodes the 70 mm bore (bore code x 5). The 125 mm OD and 40 mm height follow the ISO 104 boundary plan for that series.
Can 51314 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 51314?
At the 1,400 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 51314?
The 70/125/40 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 148 kN / C0a 340 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.