51317 bearing: complete specifications & equivalents
The 51317 is a ISO 104 radial bearing sized 85 x 150 x 49 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 85 mm |
| Outer diameter D | 150 mm |
| Width B | 49 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 206 kN |
| Basic static load rating C0 | 490 kN |
| Fatigue load limit Pu | 20.3 kN |
| Limiting speed (mechanical) | 1100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3520 g |
| Manufacturer designation | NTN 51317 |
| 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 | 3.346 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 1.929 in |
| ISO bore code | 17 |
| Radial section height (D−d)/2 | 32.5 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) | 13 of 25 |
| Bore above smallest 51300-series size | 60 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51317-SKF | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 85×150×49 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 51317 model number is decoded
The heavy-section 51300 thrust family entry 51317 stacks a shaft washer, ball-and-cage set and housing washer into 49 mm of height over a 85 mm bore. Two fields make up the code — 513 is the dimension series (heavy-section 51300 thrust family) and 17 encodes the 85 mm bore (bore code x 5). The static margin, C0a 490 kN against Ca 206 kN, is what carries slow oscillating or shock thrust without permanent raceway dents. Against a thrust roller bearing of the same 85 mm bore, this bearing is cheaper, quieter and happier at speed, but carries far less load per mm of section. On a vertical shaft, pack grease between the washers and plan a relubrication path — centrifugal effect drives grease outward and the track runs dry without it.
Typical equipment & failure modes
Common applications
- rolling-mill screwdown and adjustment screws
- heavy press and forging-machine thrust seats
- ship winch and capstan thrust shafts
- crusher main-shaft thrust supports
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
- edge loading from a shaft washer mounted off-centre, cutting the contact ellipse short at one side of the track
- cage breakage after repeated shock reversal banged the ball set against the pocket bridges
Selection pitfalls — read before you substitute
- At 85 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 150 mm OD and taller stack — check the housing space before upgrading a 512 position to this series.
- The C0a of 490 kN is a static rating: sizing continuous working thrust from C0a alone overstates what the raceway survives.
- Single-direction means exactly that: thrust on 51317 in the wrong direction separates the washers and drops the ball set — if reversal is possible even during coast-down, engineer against it.
- Shock thrust above C0a 490 kN leaves dents that later become fatigue origins — crane-hook and press applications need the static check, not just the life calculation.
- The Ca 206/C0a 490 kN ratings and 20.3 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51317; 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 51317?
51317 is a single-direction thrust ball bearing to ISO 104: 85 mm shaft-washer bore, 150 mm outside diameter, 49 mm stack height (3.346 x 5.906 x 1.929 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 206 kN, C0a 490 kN and a 20.3 kN fatigue load limit Pu; the grease limiting speed is 1,100 r/min and the oil rating 1,600 r/min; mass about 3520 g.
How is the 51317 designation structured?
513 is the dimension series (heavy-section 51300 thrust family); 17 encodes the 85 mm bore (bore code x 5). The 150 mm OD and 49 mm height follow the ISO 104 boundary plan for that series.
Can 51317 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 51317?
At the 1,100 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 51317?
The 85/150/49 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 206 kN / C0a 490 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.