322-28 bearing: complete specifications & equivalents
The 322-28 is a ISO 355 radial bearing sized 28 x 58 x 20.25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 28 mm |
| Outer diameter D | 58 mm |
| Width B | 20.25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 51.9 kN |
| Basic static load rating C0 | 50 kN |
| Fatigue load limit Pu | 5.5 kN |
| Reference speed (thermal) | 9500 rpm |
| Limiting speed (mechanical) | 12000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 250 g |
| Manufacturer designation | SKF 322/28 B |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB |
| Last verified | 2026-09-28 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB) · extracted 2026-09-28
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 & 32200-series range
| Bore d | 1.102 in |
|---|---|
| Outer diameter D | 2.283 in |
| Width B | 0.797 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 15 mm |
| Smallest bore in 32200-series | 17 mm |
| Largest outer diameter in 32200-series | 580 mm |
| Width range across 32200-series | 17.25–159 mm |
| Bore position in 32200-series (smallest first) | 4 of 36 |
| Bore above smallest 32200-series size | 11 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 322-28 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 355 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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 322-28 model number is decoded
SKF 322/28 B belongs to the SKF single-row tapered roller range — the 28 mm bore entry in the 32200 series, dimensioned 58 mm OD and 20.25 mm wide to the ISO 355 boundary plan.Numbering ties the bearing to its envelope: 322 means tapered-roller type 3, heavy section series 22, 28 mm bore — which is why the 58×20.25 mm outline swaps dimensionally with other ISO 355 bearings of the same code. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. Speed planning uses two different ceilings: 9,500 r/min thermal reference and 12,000 r/min mechanical limiting speed. For a 28 mm shaft the usual cone seat is k5 with an H7 housing when the inner ring rotates; arrange two 322 bearings as a set for two-direction location and set clearance from the load diagram, never from assembly feel. Material and manufacturing detail: the 250 g catalogue mass reflects through-hardened bearing steel (density ~7.85 g/cm³) machined to the 32200 ISO envelope, with the pressed-steel cage contributing roughly 8 g of the total; the 28 mm bore is ground to IT5 roundness and the 58 mm OD to IT5 cylindricity, and the 20.25 mm width tolerance keeps the pair-setting scatter within the ISO preload class.
Typical equipment & failure modes
Common applications
- industrial gearbox shafts and reducers
- differential and pinion drives
- pump and compressor shafts
- machine-tool spindles
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
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- On this 28 mm bore, interference and temperature rise consume clearance inside a preloaded pair; calculate the residual clearance after mounting and at operating temperature — an over-tight 322 pair heats, loses setting control and smears the roller-rib contact.
- The 322 series at 28 mm bore (58×20.25 mm) is a wider, higher-capacity section than 30222; do not substitute without re-checking shaft shoulder diameters and pair setting.
- Setting is a design value, not an assembly feel: excessive preload in the 322 pair raises operating temperature and can trigger thermal runaway, while too little lets the rollers skid and smear the raceway under light load.
- Setting is a design value, not an assembly feel: excessive preload in the 322 pair raises operating temperature and can trigger thermal runaway, while too little lets the rollers skid and smear the raceway under light load.
- Open 322 units need application-supplied sealing and a defined EP lubricant supply; the roller-rib contact is the first to fail when the additive film breaks down.
- The 51.9/50 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 322 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 322/28 B designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 322?
The SKF 322/28 B is a single-row tapered roller bearing with 28 mm bore, 58 mm outer diameter and 20.25 mm width (1.102 × 2.283 × 0.797 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 51.9 kN, C0 50 kN, fatigue load limit Pu 5.5 kN, reference speed 9,500 r/min, limiting speed 12,000 r/min, mass about 250 g. It is an open, separable bearing with a pressed-steel cage.
How does the 322 bore code work?
Non-standard bore sizes like 322 give the bore directly in millimetres after the slash, so 22 here means a 28 mm bore rather than a code × 5 value. The 58 mm OD and 20.25 mm width still follow the ISO 355 dimension-series plan for the 320 family.
What do the 322 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 22 is the ISO 355 series (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 322 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 322 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 322 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 2026-09-28. Read our editorial & correction policy.