31314-DF bearing: complete specifications & equivalents
The 31314-DF is a ISO 355 radial bearing sized 70 x 150 x 76 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 70 mm |
| Outer diameter D | 150 mm |
| Width B | 76 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 393 kN |
| Basic static load rating C0 | 440 kN |
| Fatigue load limit Pu | 54 kN |
| Reference speed (thermal) | 2600 rpm |
| Limiting speed (mechanical) | 4500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6100 g |
| Manufacturer designation | SKF 31314/DF |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants |
| Last verified | 2026-09-29 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants) · extracted 2026-09-29
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & matched-df-series range
| Bore d | 2.756 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 2.992 in |
| ISO bore code | 14 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in matched-df-series | 25 mm |
| Largest outer diameter in matched-df-series | 540 mm |
| Width range across matched-df-series | 34.5–280 mm |
| Bore position in matched-df-series (smallest first) | 10 of 35 |
| Bore above smallest matched-df-series size | 45 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 31314 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 31314-DF model number is decoded
Catalogue mass 6100 g covers both bearings and the ground spacer of 31314-DF; keep the set complete — substituting one bearing or a non-ground spacer destroys the factory clearance. Material and manufacturing detail: the 6100 g catalogue mass reflects through-hardened bearing steel machined to the listed envelope; ring roundness and width tolerance keep the mounted-setting scatter inside the catalogue class. Spacer discipline: the spacer between the two bearings of 31314-DF is ground to the individual set — it carries a serial link to the pair, so never swap spacers between sets of the same designation. A matched /DF set needs no setting adjustment at mounting: the clearance is built in; the assembler's job is clean seats, correct fits (k5 on a 70 mm rotating shaft) and square abutments.SKF 31314/DF belongs to the SKF matched tapered-roller range — the 70 mm bore entry in face-to-face (X) matched pair arrangement, dimensioned 150 mm OD and 76 mm overall width for the pair.Reading the designation: 31314 is the ISO 355 single-row base bearing (70 mm bore), and the suffix /DF marks the matched-set execution — arrangement, spacer grinding and factory clearance class. The pair envelope is 70×150×76 mm; the width covers both bearings of the set. In the face-to-face (X) arrangement the load lines of the two bearings converge toward the shaft axis: the set tolerates shaft deflection and thermal growth better than a back-to-back pair, but is less stiff against overturning moments. The 76 mm overall width of 31314-DF is the axial space the pair occupies.
Typical equipment & failure modes
Common applications
- heavy industrial gearboxes and speed reducers
- large process pump and compressor shafts
- rolling-mill auxiliary drives
- marine deck machinery shafts
Known failure patterns
- false brinelling on idle paired sets exposed to machine vibration
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- edge loading from shaft deflection or housing misalignment
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- O and X arrangements are not interchangeable by turning the set around: 31314-DF in face-to-face (X) matched pair arrangement has its load-line geometry fixed — specify the arrangement from the shaft thermal and stiffness analysis.
- Clamp the 31314-DF pair axially through the cones, never through the rollers; pressing force across the roller complement brinells the raceways of both bearings at once.
- O and X arrangements are not interchangeable by turning the set around: 31314-DF in face-to-face (X) matched pair arrangement has its load-line geometry fixed — specify the arrangement from the shaft thermal and stiffness analysis.
- The 393/440 kN ratings are SKF catalogue 17000 values for this execution; SKF can revise internal geometry without changing the order number, so keep the catalogue version (PUB BU/P1 17000/1 EN, 2018) with the specification.
- Quote the full SKF 31314/DF designation when purchasing — base-number-only orders are ambiguous across executions and variants.
Frequently asked questions
What are the dimensions and catalogue data of 31314-DF?
The SKF 31314/DF is a matched pair of single-row tapered roller bearings in face-to-face (X) matched pair arrangement with 70 mm bore, 150 mm outer diameter and 76 mm overall width (2.756 × 5.906 × 2.992 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 393 kN, C0 440 kN, fatigue load limit Pu 54 kN, reference speed 2,600 r/min, limiting speed 4,500 r/min, mass about 6.10 kg.
What does the /DF suffix on 31314-DF mean?
The base 31314 is the ISO 355 single-row bearing; the /DF suffix marks the matched-set execution — the arrangement (face-to-face (X)), the ground spacer and the factory-set axial clearance class. A matched set cannot be assembled from loose single bearings; quote the full designation when ordering.
Are the C and C0 ratings of 31314-DF for one bearing or the pair?
They are for the complete matched pair: C 393 kN dynamic and C0 440 kN static already include load sharing between the two bearings. Do not halve them for single-bearing checks, and do not compare them directly with the single-row 31314 table values.
Can 31314-DF be adjusted like two loose tapered bearings?
No — the axial clearance is set at the factory by selective spacer grinding. Mounting work is limited to clean seats, correct fits (k5 on a rotating 70 mm shaft) and axial clamping through the cones; re-setting in the field destroys the matched clearance class.
When should a face-to-face (X) matched set be chosen?
Choose the face-to-face (X) set where the shaft grows thermally or alignment is imperfect — the converging load lines tolerate deflection. It is the default choice for wheel hubs and general gearbox shafts at the 70 mm bore.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants on 2026-09-29. Read our editorial & correction policy.