51113 bearing: complete specifications & equivalents
The 51113 is a ISO 104 radial bearing sized 65 x 90 x 18 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 | 90 mm |
| Width B | 18 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 | 117 kN |
| Fatigue load limit Pu | 5.3 kN |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 338 g |
| Manufacturer designation | NTN 51113 |
| 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 | 2.559 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 0.709 in |
| ISO bore code | 13 |
| 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) | 14 of 46 |
| Bore above smallest 51100-series size | 55 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51113-SKF | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 65×90×18 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 51113 model number is decoded
NTN 51113 belongs to the light-section 51100 thrust family of single-direction thrust ball bearings: 65 / 90 / 18 mm (shaft bore / OD / height). The designation is 511 is the dimension series (light-section 51100 thrust family) plus 13 encodes the 65 mm bore (bore code x 5). Flat-seat washers make the bearing tolerant of simple housings but demand square faces: the whole 41.5 kN rating assumes the load arrives truly axial. Selection starts from the load direction: if thrust ever reverses, plan a second thrust bearing (or a double-direction execution) rather than relying on the unloaded raceway. Mount the stack in order and confirm the shaft washer sits against its shoulder before loading: pressing through the balls brinells the raceway on the spot.
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
- 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
- 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
- contamination pitting from particles settling on the horizontal housing washer — the classic failure of vertical-shaft grease-lubricated seats
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 511 light section is the speed-friendly end of the thrust-ball plan — for the same 65 mm bore it gives up load to gain OD, height and limiting-speed headroom.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51113 stack height of 18 mm and washer set differ from the double-direction execution.
- Grease in a horizontal-washer seat stays only if the housing is designed to hold it; open vertical arrangements need an oil bath or a grease-retaining cover.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51113 stack height of 18 mm and washer set differ from the double-direction execution.
- The Ca 41.5/C0a 117 kN ratings and 5.3 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51113; 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 51113?
51113 is a single-direction thrust ball bearing to ISO 104: 65 mm shaft-washer bore, 90 mm outside diameter, 18 mm stack height (2.559 x 3.543 x 0.709 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 41.5 kN, C0a 117 kN and a 5.3 kN fatigue load limit Pu; the grease limiting speed is 2,400 r/min and the oil rating 3,500 r/min; mass about 338 g.
How is the 51113 designation structured?
511 is the dimension series (light-section 51100 thrust family); 13 encodes the 65 mm bore (bore code x 5). The 90 mm OD and 18 mm height follow the ISO 104 boundary plan for that series.
Can 51113 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 51113?
At the 2,400 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 51113?
The 65/90/18 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 41.5 kN / C0a 117 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.