51314 bearing: complete specifications & equivalents
The 51314 is a ISO 104 radial bearing sized 70 x 125 x 40 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 70 mm |
| Outer diameter D | 125 mm |
| Width B | 40 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 160 kN |
| Basic static load rating C0 | 325 kN |
| Fatigue load limit Pu | 15.2 kN |
| Limiting speed (mechanical) | 1300 rpm |
| Mass | 2330 g |
| Manufacturer designation | 51314 |
| Standard | ISO 104 |
| Catalog version | CAT. No. 2203-3/E 2024 |
| Last verified | 2026-09-25 |
Source: catalog reference (CAT. No. 2203-3/E 2024) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (CAT. No. 2203-3/E 2024); 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 | 2.756 in |
|---|---|
| Outer diameter D | 4.921 in |
| Width B | 1.575 in |
| ISO bore code | 14 |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in 51300-series | 25 mm |
| Largest outer diameter in 51300-series | 170 mm |
| Width range across 51300-series | 18–55 mm |
| Bore position in 51300-series (smallest first) | 10 of 15 |
| Bore above smallest 51300-series size | 45 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 51314 model number is decoded
In the 51300-series (ISO 104 dimension series) the leading digits 513 mark a single-direction thrust ball bearing and the last two digits encode the bore: 51314 carries bore code 14 = 70 mm. The ISO 104 boundary dimensions are 70 mm bore, 125 mm outside diameter and 40 mm height. Two flat washers (shaft and housing) and a ball cage assembly allow the bearing to carry pure axial load in one direction while accommodating minor misalignment.
Typical equipment & failure modes
Common applications
- gearbox and reducer thrust management
- conveyor and elevator thrust washers
- machine tool spindle axial positioning
- paper mill roll axial restraint
Known failure patterns
- rolling-contact fatigue spalling after the rated L10 life is exceeded
- cage wear or fracture from sustained vibration or shock loading
- false brinelling from vibration while the shaft is stationary
Selection pitfalls — read before you substitute
- At a 70 mm bore, thermal expansion of the shaft can preload the thrust bearing; verify the housing washer has radial clearance to float and compensate.
- The 513xx medium section gains rating at 70 mm bore through a larger 125 mm OD and 40 mm height; the heavier assembly also trades away some speed versus a 512xx.
- Do not use a thrust ball bearing for combined radial-axial loads — pair it with a radial bearing (deep-groove or spherical roller) for the radial component.
- Single-direction thrust ball bearings carry load in one direction only; for bidirectional thrust use a double-direction bearing or two single-direction units back-to-back.
Frequently asked questions
What are the dimensions of a 51314 thrust ball bearing?
A 51314 thrust ball bearing has a 70 mm bore, 125 mm outside diameter and 40 mm height, per ISO 104 boundary dimensions. It consists of a shaft washer, housing washer and ball cage assembly.
How does the 51314 bore code work?
The last two digits of 51314 are bore code 14, giving 14 × 5 = 70 mm bore. The 125 mm outside diameter and 40 mm height follow the ISO 104 dimension series, not the bore code alone.
Can a 51314 thrust ball bearing carry radial load?
No. Single-direction thrust ball bearings carry axial load only. Any radial component must be supported by a separate radial bearing (deep-groove, cylindrical roller or spherical roller).
How does the 51300 compare with other thrust series at the same 70 mm bore?
The 513xx is the medium section: 125×40 mm, 27.5 mm radial section at 70 mm bore, carrying more load than a 512xx but needing a larger housing bore and giving up some speed.
Reviewed & verified by the MPN Base engineering desk against source catalog CAT. No. 2203-3/E 2024 on 2026-09-25. Read our editorial & correction policy.