31313 bearing: complete specifications & equivalents
The 31313 is a ISO 355 radial bearing sized 65 x 140 x 36 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 65 mm |
| Outer diameter D | 140 mm |
| Width B | 36 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 203 kN |
| Basic static load rating C0 | 193 kN |
| Fatigue load limit Pu | 23.6 kN |
| Reference speed (thermal) | 3600 rpm |
| Limiting speed (mechanical) | 4800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2350 g |
| Manufacturer designation | SKF 31313 |
| 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 | 2.559 in |
|---|---|
| Outer diameter D | 5.512 in |
| Width B | 1.417 in |
| ISO bore code | 13 |
| Radial section height (D−d)/2 | 37.5 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) | 9 of 22 |
| Bore above smallest 31300-series size | 40 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 31313 | 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 31313 model number is decoded
Ordering number SKF 31313 in SKF catalogue PUB BU/P1 17000 denotes a single-row tapered roller bearing for a 65 mm shaft, steep-angle heavy section, with an open pressed-steel-cage execution and one-direction axial capacity.Digit by digit, 31313 reads as bearing type 3 (single-row tapered roller), steep-angle heavy section series 13, and bore reference 13 resolving to 65 mm; 140 mm OD and 36 mm width are the matching ISO 355 boundary values. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. With C 203 kN and C0 193 kN, the 31313 pair-sizing check is dominated by the axial share: keep the equivalent load P below the rating at the required L10, remembering one bearing alone cannot cover reversing thrust at 4,800 r/min. A single 31313 locates the shaft in one axial direction only; mount it against a second bearing in O (back-to-back) or X (face-to-face) arrangement, and set the running clearance by the mounting procedure — not by feel.
Typical equipment & failure modes
Common applications
- crane sheave and hoist gearboxes
- paper-machine and printing rolls
- construction machinery drives
- marine deck machinery 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
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- thermal preload runaway in an O-arrangement pair when inner-ring heat expands the setting
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- grease degradation after long shelf storage without rotation or re-greasing
Selection pitfalls — read before you substitute
- Mount the 65 mm bore 31313 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 65 mm bore (140×36 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 30313 without re-running the pair calculation.
- Setting is a design value, not an assembly feel: excessive preload in the 31313 pair raises operating temperature and can trigger thermal runaway, while too little lets the rollers skid and smear the raceway under light load.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of 31313 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- The 31313 shares its ISO 355 envelope with other tapered bearings of the same code but is not a drop-in replacement for a ball bearing: it cannot run effectively under pure radial load without a minimum axial load, and a deep-groove bearing cannot replace its combined-load duty.
- The 203/193 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 31313 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 31313 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 31313?
The SKF 31313 is a single-row tapered roller bearing with 65 mm bore, 140 mm outer diameter and 36 mm width (2.559 × 5.512 × 1.417 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 203 kN, C0 193 kN, fatigue load limit Pu 23.6 kN, reference speed 3,600 r/min, limiting speed 4,800 r/min, mass about 2350 g. It is an open, separable bearing with a pressed-steel cage.
How does the 31313 bore code work?
The last two digits of 31313 are bore code 13, so 13 × 5 = 65 mm bore. The 140 mm OD and 36 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 31313 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 31313 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 31313 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 31313 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.