32311 bearing: complete specifications & equivalents
The 32311 is a ISO 355 radial bearing sized 55 x 120 x 45.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 55 mm |
| Outer diameter D | 120 mm |
| Width B | 45.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 245 kN |
| Basic static load rating C0 | 250 kN |
| Fatigue load limit Pu | 28.5 kN |
| Reference speed (thermal) | 4300 rpm |
| Limiting speed (mechanical) | 5600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2350 g |
| Manufacturer designation | SKF 32311 |
| 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 | 2.165 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 1.791 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 32.5 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) | 9 of 30 |
| Bore above smallest 32300-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32311 | 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. |
| 32311BR | 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 32311 model number is decoded
In SKF catalogue PUB BU/P1 17000, 32311 appears as SKF 32311: 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.Numbering ties the bearing to its envelope: 32311 means tapered-roller type 3, extra-heavy section series 2, 55 mm bore — which is why the 120×45.5 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. The 28.5 kN Pu figure feeds the adjusted-life equation at contaminated or partial-film conditions, and the 1.02 C0/C balance shows this execution is tuned to thrust-heavy combined loads rather than pure radial running. Specify pairs rather than single units wherever thrust reverses: the tapered contact of 32311 generates an induced axial load under radial force, and an unpaired bearing on a reversing shaft will run slack and fret its seat.
Typical equipment & failure modes
Common applications
- belt-driven fan and blower shafts
- axle-boxes in material-handling equipment
- automotive and light-truck wheel hubs
- industrial gearbox shafts and reducers
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
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- rib-roller contact scoring from loss of the EP additive film
Selection pitfalls — read before you substitute
- On this 55 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 32311 pair heats, loses setting control and smears the roller-rib contact.
- The 323 series at 55 mm bore (120×45.5 mm) is the heavy-duty section of the tapered family; it runs hotter at the same speed than a 30211, so recalculate dn and lubricant film before substitution.
- At the 245 kN rating of 32311, preload class changes stiffness by tens of percent but also heat generation; select light preload for the 5,600 r/min speed end and heavier preload only where moment stiffness dominates.
- At the 245 kN rating of 32311, preload class changes stiffness by tens of percent but also heat generation; select light preload for the 5,600 r/min speed end and heavier preload only where moment stiffness dominates.
- The 32311 shares its ISO 355 envelope with other tapered bearings of the same code but is not a drop-in replacement for a ball bearing: it cannot run effectively under pure radial load without a minimum axial load, and a deep-groove bearing cannot replace its combined-load duty.
- The 245/250 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 32311 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 32311 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 32311?
The SKF 32311 is a single-row tapered roller bearing with 55 mm bore, 120 mm outer diameter and 45.5 mm width (2.165 × 4.724 × 1.791 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 245 kN, C0 250 kN, fatigue load limit Pu 28.5 kN, reference speed 4,300 r/min, limiting speed 5,600 r/min, mass about 2350 g. It is an open, separable bearing with a pressed-steel cage.
How does the 32311 bore code work?
The last two digits of 32311 are bore code 11, so 11 × 5 = 55 mm bore. The 120 mm OD and 45.5 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 32311 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 32311 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 32311 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 32311 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.