31312 bearing: complete specifications & equivalents
The 31312 is a ISO 355 radial bearing sized 60 x 130 x 33.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 60 mm |
| Outer diameter D | 130 mm |
| Width B | 33.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 177 kN |
| Basic static load rating C0 | 166 kN |
| Fatigue load limit Pu | 20.4 kN |
| Reference speed (thermal) | 3800 rpm |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1900 g |
| Manufacturer designation | SKF 31312 |
| 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 | 2.362 in |
|---|---|
| Outer diameter D | 5.118 in |
| Width B | 1.319 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 35 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) | 8 of 22 |
| Bore above smallest 31300-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 31312 | 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 31312 model number is decoded
SKF 31312 (SKF 31312) is the steep-angle heavy section tapered roller choice for a 60 mm shaft — one row of tapered rollers on an asymmetric raceway inside the 130×33.5 mm ISO 355 envelope.Reading the designation: the leading 3 marks a single-row tapered roller bearing, the 13 is the ISO 355 diameter/width series (steep-angle heavy section), and the last two digits encode the 60 mm bore; the 130 mm OD and 33.5 mm width follow the ISO 355 general plan. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. Speed planning uses two different ceilings: 3,800 r/min thermal reference and 5,300 r/min mechanical limiting speed. Fit selection follows the rotating ring — interference on a rotating cone — and two 31312 units are required to take reversing thrust; keep the induced axial load inside the rated capacity when calculating the pair.
Typical equipment & failure modes
Common applications
- large process pump and compressor shafts
- rolling-mill auxiliary drives
- crane sheave and hoist gearboxes
- paper-machine and printing rolls
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
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- Mount the 60 mm bore 31312 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 60 mm bore (130×33.5 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 30312 without re-running the pair calculation.
- The tapered contact angle creates an induced axial load under pure radial force; include it in the 31312 rating calculation (and account for it in both bearings of a pair) or the unloaded bearing skids its rollers.
- At the 177 kN rating of 31312, preload class changes stiffness by tens of percent but also heat generation; select light preload for the 5,300 r/min speed end and heavier preload only where moment stiffness dominates.
- Catalogue reference speed and limiting speed are different limits: the 3,800 r/min reference is a thermal criterion under load, while the 5,300 r/min limiting value is the mechanical ceiling — observe both.
- The 177/166 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 31312 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 31312 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 31312?
The SKF 31312 is a single-row tapered roller bearing with 60 mm bore, 130 mm outer diameter and 33.5 mm width (2.362 × 5.118 × 1.319 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 177 kN, C0 166 kN, fatigue load limit Pu 20.4 kN, reference speed 3,800 r/min, limiting speed 5,300 r/min, mass about 1900 g. It is an open, separable bearing with a pressed-steel cage.
How does the 31312 bore code work?
The last two digits of 31312 are bore code 12, so 12 × 5 = 60 mm bore. The 130 mm OD and 33.5 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 31312 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 31312 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 31312 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 31312 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.