22308 bearing: complete specifications & equivalents
The 22308 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 |
|---|---|
| Bore diameter d | 40 mm |
| Outer diameter D | 90 mm |
| Width B | 33 mm |
| Seal / shield | open |
| Internal clearance | CN / C3 / C4 available |
| Tolerance class | P0 |
| Cage | steel |
| Operating temperature | -30 to +120 °C |
| Mass (geometry estimate) | 860 g |
| Standard | ISO 15 |
| Catalog version | iso15-srb-geometry |
| Last verified | 2026-09-24 |
Source: ISO 15 boundary-dimensions standard · extracted 2026-09-24
Standard-interchange bearing: dimensions per ISO 15; CN clearance, P0 tolerance and a stamped-steel cage are catalogue defaults unless the supplier states otherwise, and mass is a geometry-derived estimate. Brand catalogue load ratings and limiting speeds for 22308 are being backfilled — use the inquiry form for certified values.
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 | 320 mm |
| Width range across 22300-series | 33–108 mm |
| Bore position in 22300-series (smallest first) | 1 of 18 |
| Bore above smallest 22300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 22308 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 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 22308 model number is decoded
In the 22300-series (ISO 15 dimension series) the leading 2 marks a double-row spherical roller and the last two digits of 22308 encode the bore: code 08 = 40 mm (code × 5 from 04 upward). The ISO 15 envelope is 90 mm outside diameter and 33 mm width — 1.575 × 3.543 × 1.299 in, with a 25.0 mm radial section height. Two rows of symmetrical barrel rollers on a common sphered outer raceway self-align to shaft deflection while carrying heavy radial load and bidirectional axial load. Typical catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 internal clearance; K variants use a 1:12 tapered bore on an adapter sleeve — verify against the mounting arrangement.
Typical equipment & failure modes
Common applications
- elevator winches and hoist drums
- process crane travel wheels
- conveyor head and tail pulleys
- vibrating screens, feeders and shakeout machines
- paper machine felt and press rolls
Known failure patterns
- fretting corrosion on a tapered-bore sleeve seat when drive-up is insufficient and the inner ring works on the adapter
- lubricant starvation and cage wear where the relubrication interval ignores the slow-speed, dirty operating regime
- water and grit pitting of open bearings in mining and pulping duty after the housing seals degrade
- unloaded-row scuffing when pure thrust exceeds the catalogue axial capacity and one roller row unloads completely
- thermal seizure when an interference shaft fit plus hot running removes all residual radial clearance from a CN bearing
Selection pitfalls — read before you substitute
- On this 40 mm-bore 22308, specify C3 clearance as the default for an interference inner-ring fit and verify residual play after mounting; a medium-section row that ran free on the bench can be fully clamped at operating temperature on the 40 mm shaft.
- The 223 heavy wide series at 40 mm bore (90×33 mm) is selected for shock and high radial load in screens and crushers; its 25.0 mm section needs correspondingly wider shaft and housing shoulders and a stiffer shaft than a 22208 on the same journal.
- Check the shoulder geometry for 22308: a generous fillet on the 40 mm shaft looks strong but stops the 33 mm inner ring seating home; use the catalogue corner-relief radius and provide a withdrawal groove so the 25.0 mm-section outer ring presses flush in the 90 mm housing.
- Large 22308 tapers should be mounted with a hydraulic nut or oil injection: controlled drive-up sets the residual radial clearance on the 33 mm-wide double row, whereas bar-and-spanner force either under-drives (fretting) or over-drives (thermal seizure on first hot run).
- Relubricate 22308 through the W33 groove while the shaft turns slowly so fresh grease flushes the full 33 mm-wide roller set; pumping grease into a stationary bearing channels it past one row and leaves the other side of the 40 mm bore starved.
- Spherical rollers need a minimum radial load to keep the rollers driven — as a rule of thumb about 2% of the basic dynamic load rating; an unloaded 22308 on an idler or in a cold-start drive will skid and smear, so add preload, reduce the bearing size or use a sealed grease-filled variant.
- Choose the bore type deliberately: plain 22308 takes a cylindrical seat, while the K variant has a 1:12 tapered bore and mounts on an adapter sleeve (H3xx series) over a plain commercial shaft or directly on a tapered journal — the two mounting procedures are not interchangeable.
Frequently asked questions
What are the dimensions of a 22308 spherical roller bearing?
A 22308 double-row spherical roller bearing per ISO 15 has a 40 mm bore, 90 mm outer diameter and 33 mm width (1.575 × 3.543 × 1.299 in), a 25.0 mm radial section and roughly 860 g geometry-based estimated mass; catalogue masses vary with cage and design.
How does the 22308 bore code work?
The leading 2 in 22308 denotes a double-row spherical roller, the middle digits give the ISO 15 dimension series, and the last two digits are bore code 08: 08 × 5 = 40 mm. The 90 mm OD and 33 mm width come from the dimension series (22300), not from the bore code alone.
How much misalignment can a 22308 accommodate?
Thanks to the sphered outer ring raceway, 22308 normally accommodates angular misalignment of around 1° under load (up to about 2° in favourable, lightly loaded conditions); the permissible value is smaller under full load and depends on clearance and cage design, so check the catalogue figure for the actual duty.
What is the difference between 22308 and 22308K?
The plain 22308 has a cylindrical bore for a straight shaft seat. The K suffix denotes a 1:12 tapered bore, normally mounted on an H3xx adapter sleeve over a commercial shaft (or directly on a tapered journal); the bearing is driven up the sleeve to a specified residual clearance and locked with a KM nut and tab washer.
Should the 22308 be ordered with CN, C3 or C4 clearance?
Use C3 as the usual default when the rotating inner ring has an interference fit, because the fit plus thermal expansion reduces residual play; choose C4 (often with a vibratory cage design) for screens and feeders; order CN mainly for loose fits on stationary shafts or split housings. A W33 outer-ring lubrication groove is a separate, commonly combined option.
Reviewed & verified by the MPN Base engineering desk against source catalog iso15-srb-geometry on 2026-09-24. Read our editorial & correction policy.