320-22 bearing: complete specifications & equivalents
The 320-22 is a ISO 355 radial bearing sized 22 x 44 x 15 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 22 mm |
| Outer diameter D | 44 mm |
| Width B | 15 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 30.9 kN |
| Basic static load rating C0 | 29 kN |
| Fatigue load limit Pu | 2.85 kN |
| Reference speed (thermal) | 13000 rpm |
| Limiting speed (mechanical) | 15000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 100 g |
| Manufacturer designation | SKF 320/22 X |
| 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 & 32000-series range
| Bore d | 0.866 in |
|---|---|
| Outer diameter D | 1.732 in |
| Width B | 0.591 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 11 mm |
| Smallest bore in 32000-series | 20 mm |
| Largest outer diameter in 32000-series | 650 mm |
| Width range across 32000-series | 15–130 mm |
| Bore position in 32000-series (smallest first) | 2 of 43 |
| Bore above smallest 32000-series size | 2 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 320-22 | 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. |
| 320-22X | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 320-28X | NTN | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue. |
| 320-32X | NTN | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue. |
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 320-22 model number is decoded
The SKF 320/22 X is a 22×44×15 mm single-row tapered roller bearing — the low-friction section entry in the 32000 series, with an asymmetric raceway cut for thrust capacity and separable mounting.Reading the designation: the leading 3 marks a single-row tapered roller bearing, the 20 is the ISO 355 diameter/width series (low-friction section), and the last two digits encode the 22 mm bore; the 44 mm OD and 15 mm width follow the ISO 355 general plan. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. Catalogue mass 100 g for the 22×44×15 mm open execution covers the pressed-steel cage and standard roller complement; sealed or special-clearance variants differ slightly in mass and carry their own order numbers. Specify pairs rather than single units wherever thrust reverses: the tapered contact of 320 generates an induced axial load under radial force, and an unpaired bearing on a reversing shaft will run slack and fret its seat. Operating context for the 22 mm bore: a shaft of this diameter in the small-bore band typically runs between 17600 and 26400 r/min in real machinery, and the 44 mm outside diameter places the housing shoulder at 52 mm outer abutment; the 15 mm width and 100 g mass together set the shaft critical speed and the housing resonance check for this 32000-series envelope.
Typical equipment & failure modes
Common applications
- agricultural implement hubs
- small conveyor drive pulleys
- power-tool gear heads
- small automotive wheel hubs and trailer axles
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
- false brinelling on idle paired sets exposed to machine vibration
- roller large-end smearing against the cone rib after EP lubricant film failure
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- electrical pitting on VFD-driven shafts without grounding protection
Selection pitfalls — read before you substitute
- At a 22 mm bore the thin cone and cup are easily distorted by an over-tight shaft nut; check seat runout (target Ra ≤ 0.8 µm) and torque the locknut progressively — a pinched 320 shows up as gearbox vibration long before it fails.
- The 320 series at 22 mm bore (44×15 mm) is the low-friction, higher-speed section; it carries less thrust than a 30220 of the same bore, so verify the axial load share before swapping.
- O (back-to-back) pairs are stiffer against moments, X (face-to-face) pairs tolerate misalignment and thermal growth better; choosing the arrangement from the 2D drawing rather than the actual shaft thermal expansion is a common 320 mounting error.
- O (back-to-back) pairs are stiffer against moments, X (face-to-face) pairs tolerate misalignment and thermal growth better; choosing the arrangement from the 2D drawing rather than the actual shaft thermal expansion is a common 320 mounting error.
- The pressed-steel cage is rated for standard industrial service; sustained running above the limiting speed or with degraded lubricant wears the cage pockets — inspect the cage at every relubrication interval.
- The 30.9/29 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 320 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 320/22 X designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 320?
The SKF 320/22 X is a single-row tapered roller bearing with 22 mm bore, 44 mm outer diameter and 15 mm width (0.866 × 1.732 × 0.591 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 30.9 kN, C0 29 kN, fatigue load limit Pu 2.85 kN, reference speed 13,000 r/min, limiting speed 15,000 r/min, mass about 100 g. It is an open, separable bearing with a pressed-steel cage.
How does the 320 bore code work?
Non-standard bore sizes like 320 give the bore directly in millimetres after the slash, so 20 here means a 22 mm bore rather than a code × 5 value. The 44 mm OD and 15 mm width still follow the ISO 355 dimension-series plan for the 320 family.
What do the 320 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 20 is the ISO 355 series (low-friction 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 320 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 320 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 320 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.