51112 bearing: complete specifications & equivalents
The 51112 is a ISO 104 radial bearing sized 60 x 85 x 17 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 60 mm |
| Outer diameter D | 85 mm |
| Width B | 17 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 41.5 kN |
| Basic static load rating C0 | 113 kN |
| Fatigue load limit Pu | 5.1 kN |
| Limiting speed (mechanical) | 2600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 296 g |
| Manufacturer designation | NTN 51112 |
| 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 & 51100-series range
| Bore d | 2.362 in |
|---|---|
| Outer diameter D | 3.346 in |
| Width B | 0.669 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 12.5 mm |
| Smallest bore in 51100-series | 10 mm |
| Largest outer diameter in 51100-series | 640 mm |
| Width range across 51100-series | 9–85 mm |
| Bore position in 51100-series (smallest first) | 13 of 46 |
| Bore above smallest 51100-series size | 50 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51112-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 51112 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 51112 appears as a light-section 51100 thrust family bearing with a 60 mm shaft washer, a 85 mm housing diameter and 17 mm of stack height. NTN builds the number from 511 is the dimension series (light-section 51100 thrust family); 12 encodes the 60 mm bore (bore code x 5). Catalogue axial dynamic rating Ca is 41.5 kN against C0a 113 kN — a static/dynamic ratio of 2.72 that is the signature of a thrust raceway. 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 113 kN class figures at the cost of OD and height. After assembly, rotate under light load and check torque and temperature rise — a thrust ball bearing mounted with the washers swapped runs, but fails fast.
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
- 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
- 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
- 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 60 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 511 light section is the speed-friendly end of the thrust-ball plan — for the same 60 mm bore it gives up load to gain OD, height and limiting-speed headroom.
- The 2,600 r/min speed figure assumes the catalogue lubrication state; at high speed the limiting factor is often the minimum load, not the rating table.
- Swapping the shaft and housing washers is an easy assembly error on the 60 mm size — the bores differ only slightly, but the wrong pairing walks off-centre under load.
- Swapping the shaft and housing washers is an easy assembly error on the 60 mm size — the bores differ only slightly, but the wrong pairing walks off-centre under load.
- The Ca 41.5/C0a 113 kN ratings and 5.1 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51112; 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 51112?
51112 is a single-direction thrust ball bearing to ISO 104: 60 mm shaft-washer bore, 85 mm outside diameter, 17 mm stack height (2.362 x 3.346 x 0.669 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 41.5 kN, C0a 113 kN and a 5.1 kN fatigue load limit Pu; the grease limiting speed is 2,600 r/min and the oil rating 3,700 r/min; mass about 296 g.
How is the 51112 designation structured?
511 is the dimension series (light-section 51100 thrust family); 12 encodes the 60 mm bore (bore code x 5). The 85 mm OD and 17 mm height follow the ISO 104 boundary plan for that series.
Can 51112 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 51112?
At the 2,600 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 51112?
The 60/85/17 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 41.5 kN / C0a 113 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.