32309 bearing: complete specifications & equivalents
The 32309 is a ISO 355 radial bearing sized 45 x 100 x 38.25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 45 mm |
| Outer diameter D | 100 mm |
| Width B | 38.25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 173 kN |
| Basic static load rating C0 | 170 kN |
| Fatigue load limit Pu | 20.4 kN |
| Reference speed (thermal) | 5300 rpm |
| Limiting speed (mechanical) | 7000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1400 g |
| Manufacturer designation | SKF 32309 |
| 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 | 1.772 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 1.506 in |
| ISO bore code | 09 |
| Radial section height (D−d)/2 | 27.5 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) | 7 of 30 |
| Bore above smallest 32300-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32309 | 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. |
| 32309BR | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Flanged-cup variant of this base bearing: same d/D/T boundary, different housing location concept — not a drop-in substitute where the flange is the axial register. |
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 32309 model number is decoded
32309 is a single-row tapered roller bearing in the ISO 32300 dimension series: a separable cone-and-cup design for combined radial and one-direction axial load, listed by SKF in SKF catalogue PUB BU/P1 17000.On the SKF nameplate, 32309 follows the ISO 355 convention: 3 for the tapered-roller type, 2 for the extra-heavy section, final digits 09 for the 45 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. At 5,300 r/min reference speed the 27.5 mm-section 32309 is governed thermally by preload and lubricant flow; grease or oil selection should be made against that value, with 7,000 r/min as the mechanical ceiling. For a 45 mm shaft the usual cone seat is k5 with an H7 housing when the inner ring rotates; arrange two 32309 bearings as a set for two-direction location and set clearance from the load diagram, never from assembly feel.
Typical equipment & failure modes
Common applications
- axle-boxes in material-handling equipment
- automotive and light-truck wheel hubs
- industrial gearbox shafts and reducers
- differential and pinion drives
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
- thermal preload runaway in an O-arrangement pair when inner-ring heat expands the setting
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- hard-particle indentation of the tapered raceway in unfiltered oil
Selection pitfalls — read before you substitute
- On this 45 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 32309 pair heats, loses setting control and smears the roller-rib contact.
- The 323 series at 45 mm bore (100×38.25 mm) is the heavy-duty section of the tapered family; it runs hotter at the same speed than a 30209, so recalculate dn and lubricant film before substitution.
- A single 32309 cannot locate the shaft axially in both directions; mounting it singly on a reversing-thrust shaft leaves one direction uncontrolled — always use an O or X matched pair for bidirectional location.
- At the 173 kN rating of 32309, preload class changes stiffness by tens of percent but also heat generation; select light preload for the 7,000 r/min speed end and heavier preload only where moment stiffness dominates.
- The 1400 g mass and 38.25 mm width mean spacer and abutment faces must be square to the axis within the bearing's own P0 tolerance; a tilted spacer tilts the contact angle and concentrates load on one rib of 32309.
- The 173/170 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 32309 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 32309 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 32309?
The SKF 32309 is a single-row tapered roller bearing with 45 mm bore, 100 mm outer diameter and 38.25 mm width (1.772 × 3.937 × 1.506 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 173 kN, C0 170 kN, fatigue load limit Pu 20.4 kN, reference speed 5,300 r/min, limiting speed 7,000 r/min, mass about 1400 g. It is an open, separable bearing with a pressed-steel cage.
How does the 32309 bore code work?
The last two digits of 32309 are bore code 09, so 09 × 5 = 45 mm bore. The 100 mm OD and 38.25 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 32309 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 32309 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 32309 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 32309 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.