32304 bearing: complete specifications & equivalents
The 32304 is a ISO 355 radial bearing sized 20 x 52 x 22.25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 20 mm |
| Outer diameter D | 52 mm |
| Width B | 22.25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 54.3 kN |
| Basic static load rating C0 | 45.5 kN |
| Fatigue load limit Pu | 5 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 14000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 230 g |
| Manufacturer designation | SKF 32304 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB) · extracted 2026-09-26
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 & 32300-series range
| Bore d | 0.787 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.876 in |
| ISO bore code | 04 |
| Radial section height (D−d)/2 | 16 mm |
| Smallest bore in 32300-series | 20 mm |
| Largest outer diameter in 32300-series | 460 mm |
| Width range across 32300-series | 22.25–154 mm |
| Bore position in 32300-series (smallest first) | 1 of 30 |
| Bore above smallest 32300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32304 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 32304-NTN | 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. |
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 32304 model number is decoded
In SKF catalogue PUB BU/P1 17000, 32304 appears as SKF 32304: an open, single-row tapered roller bearing in the extra-heavy section of the 32300 dimension series, supplied with a pressed-steel cage as standard.On the SKF nameplate, 32304 follows the ISO 355 convention: 3 for the tapered-roller type, 2 for the extra-heavy section, final digits 04 for the 20 mm bore. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. With C 54.3 kN and C0 45.5 kN, the 32304 pair-sizing check is dominated by the axial share: keep the equivalent load P below the rating at the required L10, remembering one bearing alone cannot cover reversing thrust at 14,000 r/min. Fit selection follows the rotating ring — interference on a rotating cone — and two 32304 units are required to take reversing thrust; keep the induced axial load inside the rated capacity when calculating the pair.
Typical equipment & failure modes
Common applications
- steering knuckles and small differentials
- agricultural implement hubs
- small conveyor drive pulleys
- power-tool gear heads
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
- brinelling from pressing the cone or cup home through the rollers
Selection pitfalls — read before you substitute
- At a 20 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 32304 shows up as gearbox vibration long before it fails.
- The 323 series at 20 mm bore (52×22.25 mm) is the heavy-duty section of the tapered family; it runs hotter at the same speed than a 30204, so recalculate dn and lubricant film before substitution.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of 32304 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- Do not mix brands or executions inside one 32304 pair — matched sets are ground for a specific setting, and pairing a SKF basic unit with a different suffix variant will not share the setting evenly.
- Shaft and housing fillets must clear the bearing chamfer so the 22.25 mm-wide cup seats square; use an undercut or withdrawal groove rather than an oversized radius that locks on the ring face.
- The 54.3/45.5 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 32304 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 32304 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 32304?
The SKF 32304 is a single-row tapered roller bearing with 20 mm bore, 52 mm outer diameter and 22.25 mm width (0.787 × 2.047 × 0.876 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 54.3 kN, C0 45.5 kN, fatigue load limit Pu 5 kN, reference speed 11,000 r/min, limiting speed 14,000 r/min, mass about 230 g. It is an open, separable bearing with a pressed-steel cage.
How does the 32304 bore code work?
The last two digits of 32304 are bore code 04, so 04 × 5 = 20 mm bore. The 52 mm OD and 22.25 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 32304 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 2 is the ISO 355 series (extra-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 32304 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 32304 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 32304 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 2026-09-26. Read our editorial & correction policy.