21313-EK bearing: complete specifications & equivalents
The 21313-EK 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 | 2900 g |
| Manufacturer designation | SKF 21313 EK |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.2 adapter-sleeve executions |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.2 adapter-sleeve executions) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.2 adapter-sleeve executions); 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. |
| 21313 | SKF | full Dimensions and internal design equivalent — standard interchange. | Tapered-bore (1:12) sleeve-mounted execution of 21313; identical ISO 15 envelope, fits H313 adapter sleeve on a 60 mm shaft. |
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-EK model number is decoded
For sleeve mounting on a 65 mm shaft, SKF order number SKF 21313 EK is the 1:12 tapered-bore spherical roller bearing in the 21300-series family (dimension series 13 (heavy OD, normal width)); the cylindrical-bore equivalent is a separate order number, 21313. Digit by digit, 21313-ek reads as bearing type 2 (spherical roller, two barrel-roller rows), dimension series 13, and bore reference 13 resolving to 65 mm; 140 mm OD and 33 mm width are the matching ISO 15 boundary values. The K in the designation marks the 1:12 tapered bore: SKF mounts it on an H-series adapter sleeve (with KM locknut and MB lock washer) on a plain commercial-grade shaft, or on an AH withdrawal sleeve where the bearing must abut a shaft shoulder. At 4,300 r/min reference speed the 37.5 mm-section 21313-ek is governed thermally by lubricant flow through the W33 groove and the two-row roller complement; grease or oil selection should be made against that value, with 6,000 r/min as the mechanical ceiling. On an H adapter sleeve the 65 mm shaft seat only needs an h9 plain journal; slide the sleeve into the 21313-ek inner ring, tighten the KM nut against the MB washer until the catalogue clearance-reduction value is reached, then lock the washer tab.
Typical equipment & failure modes
Common applications
- heavy conveyor head shafts in mining
- jaw and cone crusher main shafts
- split-housing plummer block arrangements with bearings swapped in situ
- heavy crusher and screen shafts mounted and dismounted with hydraulic nuts
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
- sleeve seizure and shaft seat damage from omitting the anti-seize film between withdrawal sleeve and journal before drive-up
- surface distress and smearing when the relubrication interval is exceeded — the W33 groove is only effective if grease actually reaches the roller rows
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- Mount the 65 mm bore 21313-ek 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.
- Never apply the drive-up or clearance-reduction figures for this 1:12 tapered 21313-ek to a bearing of the other taper (1:12 vs 1:30); the steeper taper moves far less clearance per nut turn and the targets come from different catalogue tables.
- The 21313-ek and its cylindrical-bore counterpart 21313 share envelope and load ratings (243/270 kN) but are not interchangeable in a housing already fitted for direct shaft mounting — the sleeve changes the assembly stack-up.
- Never use the tapered-bore EK/K variant's drive-up figures on this cylindrical-bore 21313-ek; clearance reduction targets differ, and over-driving a cylindrical bore onto an oversized journal cracks the inner ring.
- The 243/270 kN ratings are SKF catalogue values for this tapered-bore execution (SKF 21313 EK); sleeve, KM nut and MB washer are separate order numbers, and the catalogue version (SKF catalogue PUB BU/P1 17000) should travel with the mounting specification.
Frequently asked questions
What are the dimensions and catalogue data of 21313-ek?
The SKF 21313 EK is a double-row spherical roller bearing with a 1:12 tapered bore, 65 mm nominal 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: C 243 kN, C0 270 kN, Pu 29 kN, reference speed 4,300 r/min, limiting speed 6,000 r/min, mass about 2900 g. It is mounted on an adapter (H) or withdrawal (AH) sleeve, not directly on the shaft.
What does the K suffix mean on 21313-ek?
K marks a 1:12 tapered bore for sleeve mounting — SKF writes EK or CCK(/W33), FAG writes -K- inside the suffix chain for sleeve mounting. The bearing seats on an H-series adapter sleeve with a KM locknut and MB lock washer (plain shaft, h9 tolerance), or on an AH withdrawal sleeve against a shaft shoulder. The rarer K30 suffix would instead mean a 1:30 taper; dimension series 40/41 spherical rollers commonly use it.
Which adapter sleeve fits the 21313-ek?
The sleeve is selected by the actual shaft diameter in millimetres, not only by the 65 mm nominal bore: SKF H-sleeve numbers each cover a small shaft-diameter range and are width-series specific (H39/H30/H31/H32 matching dimension series 39/40/31/32), and each kit bundles the sleeve, KM locknut and MB lock washer. For shoulder locations use an AH withdrawal sleeve instead. Confirm the sleeve number against the SKF catalogue PUB BU/P1 17000 mounting tables for your shaft size.
How is the 21313-ek driven up and checked?
Mounting is controlled by radial-clearance reduction or axial drive-up distance from the SKF catalogue tables for the 1:12 taper, never by locknut torque. Measure clearance with feeler gauges before and after tightening the KM nut, stop at the tabulated decrease, and lock the MB washer tab. Over-drive removes too much clearance (inner-ring cracking risk); under-drive lets the sleeve creep and fret.
What is the difference between 21313-ek and 21313?
They share the ISO 15 envelope and the same 243/270 kN ratings, but 21313-ek has the 1:12 tapered bore for sleeve mounting on a plain shaft, while 21313 has a cylindrical bore for direct mounting on a machined interference journal (typically k5 with H7 housing). They are separate order numbers, not interchangeable in the same shaft arrangement.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.2 adapter-sleeve executions on 2026-09-26. Read our editorial & correction policy.