22308-EK bearing: complete specifications & equivalents
The 22308-EK is a ISO 15 radial bearing sized 40 x 90 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 | 40 mm |
| Outer diameter D | 90 mm |
| Width B | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 155 kN |
| Basic static load rating C0 | 140 kN |
| Fatigue load limit Pu | 15 kN |
| Reference speed (thermal) | 6000 rpm |
| Limiting speed (mechanical) | 8000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1250 g |
| Manufacturer designation | SKF 22308 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 & 22300-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 1.299 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 25 mm |
| Smallest bore in 22300-series | 40 mm |
| Largest outer diameter in 22300-series | 620 mm |
| Width range across 22300-series | 33–185 mm |
| Bore position in 22300-series (smallest first) | 1 of 28 |
| Bore above smallest 22300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 22308 | SKF | full Dimensions and internal design equivalent — standard interchange. | Tapered-bore (1:12) sleeve-mounted execution of 22308; identical ISO 15 envelope, fits H2308 adapter sleeve on a 35 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 22308-EK model number is decoded
For sleeve mounting on a 40 mm shaft, SKF order number SKF 22308 EK is the 1:12 tapered-bore spherical roller bearing in the 22300-series family (dimension series 23 (heavy OD, wide)); the cylindrical-bore equivalent is a separate order number, 22308. On the SKF nameplate, 22308-ek follows the ISO 15 convention: 2 for the spherical roller type, 23 for the dimension series 23 (heavy OD, wide), final digits 08 for the 40 mm bore. Note that K means 1:12 taper; the rarer K30 suffix means 1:30. Adapter sleeves (H) and withdrawal sleeves (AH) are ordered separately by shaft diameter, and the KM locknut plus MB lock washer used for drive-up are also separate components. Selection arithmetic: the C0/C ratio is about 0.90 (static 140 kN against dynamic 155 kN), typical of a spherical roller sized for heavy combined loads, and the 15 kN fatigue load limit Pu is the equivalent-load floor used in the life calculation. At 40 mm bore, dismount after service is by KM locknut reversal or a hydraulic nut on larger sizes; oil-injection grooves on the bigger sleeves let pressurised oil float the 22308-ek off the taper without scoring either surface.
Typical equipment & failure modes
Common applications
- vibrating screen and scalper main shafts
- conveyor drive and bend pulleys
- heavy crusher and screen shafts mounted and dismounted with hydraulic nuts
- long through-shafts in conveyors, where a sleeve seat avoids a precision journal
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
- inner-ring circumferential cracking after over-drive on the tapered seat removes too much radial clearance and the bearing runs preloaded
- roller-end scoring from starved lubricant at start-up before the grease channel purges
- seal-lip wear and grease purge loss when an open bearing is run without functioning housing seals
Selection pitfalls — read before you substitute
- On this 40 mm bore, an interference inner-ring fit consumes a large share of the CN clearance; specify C3 when the inner ring rotates hot, and verify residual clearance after mounting rather than trusting the catalogue clearance class.
- The 22300-series series at 40 mm bore (90×33 mm) is the heavy wide-section choice — highest capacity, lowest speed limit; do not substitute a 222 or 230 series in the same bore without re-checking both life and the 8,000 r/min ceiling.
- A loose sleeve after the first weeks of service usually means inadequate initial drive-up; re-checking clearance without dismounting is possible through the 33 mm-wide roller rows with feeler gauges — do not simply tighten the KM nut until vibration stops.
- Never apply the drive-up or clearance-reduction figures for this 1:12 tapered 22308-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.
- 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 22308-ek pits long before its L10 life.
- The 155/140 kN ratings are SKF catalogue values for this tapered-bore execution (SKF 22308 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 22308-ek?
The SKF 22308 EK is a double-row spherical roller bearing with a 1:12 tapered bore, 40 mm nominal bore, 90 mm outer diameter and 33 mm width (1.575 × 3.543 × 1.299 in) per ISO 15. From SKF catalogue PUB BU/P1 17000: C 155 kN, C0 140 kN, Pu 15 kN, reference speed 6,000 r/min, limiting speed 8,000 r/min, mass about 1250 g. It is mounted on an adapter (H) or withdrawal (AH) sleeve, not directly on the shaft.
What does the K suffix mean on 22308-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 22308-ek?
The sleeve is selected by the actual shaft diameter in millimetres, not only by the 40 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 22308-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 22308-ek and 22308?
They share the ISO 15 envelope and the same 155/140 kN ratings, but 22308-ek has the 1:12 tapered bore for sleeve mounting on a plain shaft, while 22308 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.