31314 bearing: complete specifications & equivalents
The 31314 is a ISO 355 radial bearing sized 70 x 150 x 38 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 | 38 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 229 kN |
| Basic static load rating C0 | 220 kN |
| Fatigue load limit Pu | 27 kN |
| Reference speed (thermal) | 3400 rpm |
| Limiting speed (mechanical) | 4500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2850 g |
| Manufacturer designation | SKF 31314 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB); 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 & 31300-series range
| Bore d | 2.756 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 1.496 in |
| ISO bore code | 14 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in 31300-series | 25 mm |
| Largest outer diameter in 31300-series | 320 mm |
| Width range across 31300-series | 18.25–82 mm |
| Bore position in 31300-series (smallest first) | 10 of 22 |
| Bore above smallest 31300-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 355 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 model number is decoded
31314 is a single-row tapered roller bearing in the ISO 31300 dimension series: a separable cone-and-cup design for combined radial and one-direction axial load, listed by SKF in SKF catalogue PUB BU/P1 17000.Numbering ties the bearing to its envelope: 31314 means tapered-roller type 3, steep-angle heavy section series 13, 70 mm bore — which is why the 150×38 mm outline swaps dimensionally with other ISO 355 bearings of the same code. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. The 27 kN Pu figure feeds the adjusted-life equation at contaminated or partial-film conditions, and the 0.96 C0/C balance shows this execution is tuned to thrust-heavy combined loads rather than pure radial running. Note the minimum-axial-load requirement: at light radial load and high speed the rollers of 31314 must still be held into the rib contact, which is another reason the catalogue recommends paired mounting with controlled setting.
Typical equipment & failure modes
Common applications
- construction machinery drives
- marine deck machinery shafts
- heavy industrial gearboxes and speed reducers
- large process pump and compressor shafts
Known failure patterns
- cup or cone misalignment when the separable rings are not seated square during mounting
- loose cup rotation in the housing when the specified press fit is not achieved
- roller large-end smearing against the cone rib after EP lubricant film failure
- false brinelling on idle paired sets exposed to machine vibration
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- Mount the 70 mm bore 31314 by induction heating of the cone (max 120 °C — the pressed-steel cage sets the ceiling, not the steel); driving it home through the cup or rollers brinells the tapered raceway.
- The 313 series at 70 mm bore (150×38 mm) has a steeper contact angle than the 302/303 families — higher axial capacity per radial load but more induced thrust and heat; do not interchange with a 30314 without re-running the pair calculation.
- A single 31314 cannot locate the shaft axially in both directions; mounting it singly on a reversing-thrust shaft leaves one direction uncontrolled — always use an O or X matched pair for bidirectional location.
- Do not mix brands or executions inside one 31314 pair — matched sets are ground for a specific setting, and pairing a SKF basic unit with a different suffix variant will not share the setting evenly.
- Never press both rings through the wrong element during fitting: force for an interference shaft seat goes through the cone only, or brinell marks on the 150 mm cup race release as noise within the first running hours.
- The 229/220 kN ratings are SKF catalogue 17000 values for the basic 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 and re-verify for critical drives.
- SKF lists several executions of 31314 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 31314 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 31314?
The SKF 31314 is a single-row tapered roller bearing with 70 mm bore, 150 mm outer diameter and 38 mm width (2.756 × 5.906 × 1.496 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 229 kN, C0 220 kN, fatigue load limit Pu 27 kN, reference speed 3,400 r/min, limiting speed 4,500 r/min, mass about 2850 g. It is an open, separable bearing with a pressed-steel cage.
How does the 31314 bore code work?
The last two digits of 31314 are bore code 14, so 14 × 5 = 70 mm bore. The 150 mm OD and 38 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 31314 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 13 is the ISO 355 series (steep-angle heavy section). The SKF catalogue lists the ISO 355 dimension-series code after the bare number. A steeper-contact-angle variant (B suffix) is a different order number and is not interchangeable with the basic execution.
Can a single 31314 take axial load in both directions?
No — one single-row tapered roller bearing reacts thrust in one direction only, and under radial load its contact angle induces an axial force. Use two bearings as a matched pair: O (back-to-back) for a rigid, moment-resisting arrangement, X (face-to-face) where thermal expansion must be tolerated, or tandem where one-direction thrust is shared.
How does 31314 compare with a ball bearing of the same bore?
A tapered roller bearing has line contact and a steep contact angle: much higher combined axial-plus-radial capacity and shock resistance than a ball bearing of the same bore, at the cost of speed, one-direction thrust, mandatory pairing for reversing loads and a minimum axial load requirement. A ball bearing cannot be dropped into a combined-load 31314 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB on 2026-09-26. Read our editorial & correction policy.