51416 bearing: complete specifications & equivalents
The 51416 is a ISO 104 radial bearing sized 80 x 170 x 68 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 80 mm |
| Outer diameter D | 170 mm |
| Width B | 68 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 270 kN |
| Basic static load rating C0 | 620 kN |
| Fatigue load limit Pu | 25 kN |
| Limiting speed (mechanical) | 890 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 7770 g |
| Manufacturer designation | NTN 51416 |
| 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 & 51400-series range
| Bore d | 3.15 in |
|---|---|
| Outer diameter D | 6.693 in |
| Width B | 2.677 in |
| ISO bore code | 16 |
| Radial section height (D−d)/2 | 45 mm |
| Smallest bore in 51400-series | 25 mm |
| Largest outer diameter in 51400-series | 300 mm |
| Width range across 51400-series | 24–120 mm |
| Bore position in 51400-series (smallest first) | 12 of 20 |
| Bore above smallest 51400-series size | 55 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51416-M | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 80×170×68 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 51416 model number is decoded
At 80 x 170 x 68 mm, NTN 51416 sits in the extra-heavy 51400 thrust family of the single-direction thrust programme. Decoding 51416: 514 is the dimension series (extra-heavy 51400 thrust family), with 16 encodes the 80 mm bore (bore code x 5). On speed, the grease limiting speed is 890 r/min and the oil rating 1,300 r/min. Within the thrust-ball plan, 511 is the light section and 514 the heaviest for a given bore; moving up a series raises the C0a from 620 kN class figures at the cost of OD and height. 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
- ship winch and capstan thrust shafts
- crusher main-shaft thrust supports
- large rotary-table and index-table thrust rings
- vertical water-pump and turbine thrust blocks
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
- 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
- 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
- At 80 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 514 extra-heavy section is the top of the thrust-ball plan at this bore; beyond it the catalogue moves to spherical roller thrust bearings.
- The 890 r/min speed figure assumes the catalogue lubrication state; at high speed the limiting factor is often the minimum load, not the rating table.
- Radial load is the silent killer here: a belt pull or gear force on the same shaft must land on a radial bearing, because 51416 has no radial capacity at all.
- A housing washer pressed tight in its seat cannot self-centre; the resulting eccentric running shows up as cage wear long before raceway fatigue.
- The Ca 270/C0a 620 kN ratings and 25 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51416; 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 51416?
51416 is a single-direction thrust ball bearing to ISO 104: 80 mm shaft-washer bore, 170 mm outside diameter, 68 mm stack height (3.15 x 6.693 x 2.677 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 270 kN, C0a 620 kN and a 25 kN fatigue load limit Pu; the grease limiting speed is 890 r/min and the oil rating 1,300 r/min; mass about 7770 g.
How is the 51416 designation structured?
514 is the dimension series (extra-heavy 51400 thrust family); 16 encodes the 80 mm bore (bore code x 5). The 170 mm OD and 68 mm height follow the ISO 104 boundary plan for that series.
Can 51416 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 51416?
At the 890 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 51416?
The 80/170/68 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 270 kN / C0a 620 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.