51313 bearing: complete specifications & equivalents
The 51313 is a ISO 104 radial bearing sized 65 x 115 x 36 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 65 mm |
| Outer diameter D | 115 mm |
| Width B | 36 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 128 kN |
| Basic static load rating C0 | 287 kN |
| Fatigue load limit Pu | 13 kN |
| Limiting speed (mechanical) | 1500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1510 g |
| Manufacturer designation | NTN 51313 |
| 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 | 2.559 in |
|---|---|
| Outer diameter D | 4.528 in |
| Width B | 1.417 in |
| ISO bore code | 13 |
| Radial section height (D−d)/2 | 25 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) | 9 of 25 |
| Bore above smallest 51300-series size | 40 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51313-SKF | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 65×115×36 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 51313 model number is decoded
From the heavy-section 51300 thrust family, 51313 measures 65 mm through the shaft washer, 115 mm over the outside and 36 mm in assembled height. Decoding 51313: 513 is the dimension series (heavy-section 51300 thrust family), with 13 encodes the 65 mm bore (bore code x 5). Catalogue axial dynamic rating Ca is 128 kN against C0a 287 kN — a static/dynamic ratio of 2.24 that is the signature of a thrust raceway. 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. Preload or working clearance must guarantee the minimum axial load at the catalogue speed; a spring or dead-weight arrangement is the usual answer on high-speed vertical shafts.
Typical equipment & failure modes
Common applications
- large crane hook and swivel assemblies
- rolling-mill screwdown and adjustment screws
- heavy press and forging-machine thrust seats
- ship winch and capstan thrust 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
- 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
- At 65 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 115 mm OD and taller stack — check the housing space before upgrading a 512 position to this series.
- The 1,500 r/min speed figure assumes the catalogue lubrication state; at high speed the limiting factor is often the minimum load, not the rating table.
- A housing washer pressed tight in its seat cannot self-centre; the resulting eccentric running shows up as cage wear long before raceway fatigue.
- Swapping the shaft and housing washers is an easy assembly error on the 65 mm size — the bores differ only slightly, but the wrong pairing walks off-centre under load.
- The Ca 128/C0a 287 kN ratings and 13 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51313; 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 51313?
51313 is a single-direction thrust ball bearing to ISO 104: 65 mm shaft-washer bore, 115 mm outside diameter, 36 mm stack height (2.559 x 4.528 x 1.417 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 128 kN, C0a 287 kN and a 13 kN fatigue load limit Pu; the grease limiting speed is 1,500 r/min and the oil rating 2,200 r/min; mass about 1510 g.
How is the 51313 designation structured?
513 is the dimension series (heavy-section 51300 thrust family); 13 encodes the 65 mm bore (bore code x 5). The 115 mm OD and 36 mm height follow the ISO 104 boundary plan for that series.
Can 51313 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 51313?
At the 1,500 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 51313?
The 65/115/36 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 128 kN / C0a 287 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.