21313 bearing: complete specifications & equivalents
The 21313 is a ISO 15 radial bearing sized 65 x 140 x 33 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 | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 243 kN |
| Basic static load rating C0 | 270 kN |
| Fatigue load limit Pu | 29 kN |
| Reference speed (thermal) | 4300 rpm |
| Limiting speed (mechanical) | 6000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2550 g |
| Manufacturer designation | SKF 21313 E |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.1 spherical roller bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.1 spherical roller bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.1 spherical roller bearings); 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 & 21300-series range
| Bore d | 2.559 in |
|---|---|
| Outer diameter D | 5.512 in |
| Width B | 1.299 in |
| ISO bore code | 13 |
| Radial section height (D−d)/2 | 37.5 mm |
| Smallest bore in 21300-series | 40 mm |
| Largest outer diameter in 21300-series | 240 mm |
| Width range across 21300-series | 23–50 mm |
| Bore position in 21300-series (smallest first) | 6 of 14 |
| Bore above smallest 21300-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 21313-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 65×140×33 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 6313 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Identical envelope but a different bearing type — confirm load and speed suitability before substitution. |
| 6313-2RS | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Identical envelope but a different bearing type — confirm load and speed suitability before substitution. |
| 6313-ZZ | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Identical envelope but a different bearing type — confirm load and speed suitability before substitution. |
| 21313-EK | SKF | full Dimensions and internal design equivalent — standard interchange. | Tapered-bore (1:12) execution on H313 adapter sleeve; same ISO 15 envelope, separate order number. |
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 21313 model number is decoded
SKF 21313 (21313 E) is the spherical-roller choice for a 65 mm shaft — barrel rollers between an inner ring with two raceways and a common sphered outer raceway inside the 140×33 mm ISO 15 envelope. The code breaks down as type digit 2 (double-row spherical roller), dimension series 13 (dimension series 13 (heavy OD, normal width)), and bore code 13 = 65 mm; dimensions 65×140×33 mm therefore match the ISO 15 envelope. The trailing E is the SKF optimized internal design: larger rollers and a stamped window-type steel cage give higher load ratings than the older CC geometry; EK is the same bearing with a 1:12 tapered bore for adapter sleeves. Speed planning uses two different ceilings: 4,300 r/min thermal reference and 6,000 r/min mechanical limiting speed. Mount with the spherical bearing's self-alignment in mind: it compensates ≈ 0.5–2.5° of misalignment depending on series, but the shaft and housing seats still set the datum — a rotating inner ring on a 65 mm shaft typically takes a k5 seat with an H7 housing bore.
Typical equipment & failure modes
Common applications
- paper-machine press and dryer rolls
- rolling-mill pinion and back-up shafts
- large vibrating screens and feeders
- marine propulsion and thruster shafts
Known failure patterns
- raceway fatigue spalling of the sphered outer raceway after extended service above the catalogue L10 rating
- inner-ring raceway spalling from edge loading when misalignment exceeds the self-aligning recovery range
- cage pocket wear or fracture from roller skew at insufficient minimum load or rapid acceleration
- roller-end scoring from starved lubricant at start-up before the grease channel purges
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- Mount the 65 mm bore 21313 by induction heating (max 120 °C) or oil injection — driving a bearing of this section home through the rollers brinells both raceways, and the damage only speaks up as vibration hours later.
- The 21300-series series at 65 mm bore (140×33 mm) pairs a heavy OD with a narrow section — a compact way to add capacity, but the shoulder and abutment diameters differ from the 222 series; it is not a drop-in swap.
- The self-aligning feature is not a license to ignore alignment: beyond ≈ 0.5–2.5° (series-dependent) the edge loading eats the fatigue margin, and seal drag grows as the rings tilt.
- Open spherical roller bearings rely on the housing seals; in screening or crusher duty a failed seal lets grit into the sphered raceway and the 21313 pits long before its L10 life.
- The 243/270 kN ratings are SKF catalogue values for this exact execution (21313 E); SKF can revise internal geometry without changing the order number, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the specification and re-verify for critical drives.
- SKF lists several executions of 21313 (cylindrical bore as listed, tapered-bore 21313 EK variant, plus sealed and vibrating-screen options in the same envelope); they are not interchangeable order numbers — quote the full 21313 E designation when purchasing.
Frequently asked questions
What are the dimensions and catalogue data of 21313?
The 21313 E is a double-row spherical roller bearing with 65 mm bore, 140 mm outer diameter and 33 mm width (2.559 × 5.512 × 1.299 in) per ISO 15. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 243 kN, C0 270 kN, fatigue load limit Pu 29 kN, reference speed 4,300 r/min, limiting speed 6,000 r/min, mass about 2550 g. It is an open, self-aligning bearing with a stamped window-type steel cage.
How does the 21313 bore code work?
The last two digits of 21313 are bore code 13, so 13 × 5 = 65 mm bore. The 140 mm OD and 33 mm width come from the ISO 15 dimension-series plan (dimension series 13 (heavy OD, normal width)), shared with other spherical roller bearings of the same code.
What does the E suffix mean on 21313?
E is the SKF optimized internal design with larger rollers and a stamped window-type steel cage for higher load ratings. The EK variant is the same bearing with a 1:12 tapered bore for adapter sleeves.
Can 21313 accommodate misalignment and axial load?
Yes on both counts. The sphered outer raceway lets the bearing self-align ≈ 0.5–2.5° depending on series, absorbing shaft deflection and housing-seat errors. The two barrel-roller rows also carry bidirectional axial load in addition to heavy radial load — this is the key difference from cylindrical roller bearings, which take no axial load.
When should the tapered-bore 21313K variant be used instead?
Choose the K (1:12 tapered bore) variant when the bearing must seat on an adapter or withdrawal sleeve — typical for long shafts, frequent dismounting, or stepped shafts where machining a precision journal is impractical. Sleeve mounting requires measuring clearance reduction or axial drive-up, not nut torque. The cylindrical-bore 21313 listed here seats directly on a machined journal.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.1 spherical roller bearings on 2026-09-26. Read our editorial & correction policy.