33111 bearing: complete specifications & equivalents
The 33111 is a ISO 355 radial bearing sized 55 x 95 x 30 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 | 95 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 136 kN |
| Basic static load rating C0 | 156 kN |
| Fatigue load limit Pu | 17.6 kN |
| Reference speed (thermal) | 5600 rpm |
| Limiting speed (mechanical) | 6700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 850 g |
| Manufacturer designation | SKF 33111 |
| 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 & 33100-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 3.74 in |
| Width B | 1.181 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 20 mm |
| Smallest bore in 33100-series | 40 mm |
| Largest outer diameter in 33100-series | 180 mm |
| Width range across 33100-series | 26–56 mm |
| Bore position in 33100-series (smallest first) | 4 of 12 |
| Bore above smallest 33100-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33111 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 355 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 33111 model number is decoded
SKF 33111 belongs to the SKF single-row tapered roller range — the 55 mm bore entry in the 33100 series, dimensioned 95 mm OD and 30 mm wide to the ISO 355 boundary plan.The code breaks down as type prefix 3 (tapered roller), series 31 (the light wide section), and bore code 11 = 55 mm; dimensions 55×95×30 mm therefore match the ISO 355 envelope. In SKF suffix language a bare 33111 is the standard execution; B marks a larger contact angle and Q or J2 mark clearance/cage variants, all quoted separately. Speed planning uses two different ceilings: 5,600 r/min thermal reference and 6,700 r/min mechanical limiting speed. Specify pairs rather than single units wherever thrust reverses: the tapered contact of 33111 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
- 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
- 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
- fretting corrosion on a loose rotating shaft seat
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 33111 pair heats, loses setting control and smears the roller-rib contact.
- The 331 series at 55 mm bore (95×30 mm) pairs a small OD with a wide section — a compact way to add capacity where radial space is tight; abutment and spacer widths differ from the 330/302 families, so it is not a drop-in swap.
- Do not mix brands or executions inside one 33111 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.
- The tapered contact angle creates an induced axial load under pure radial force; include it in the 33111 rating calculation (and account for it in both bearings of a pair) or the unloaded bearing skids its rollers.
- Shaft and housing fillets must clear the bearing chamfer so the 30 mm-wide cup seats square; use an undercut or withdrawal groove rather than an oversized radius that locks on the ring face.
- The 136/156 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 33111 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 33111 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 33111?
The SKF 33111 is a single-row tapered roller bearing with 55 mm bore, 95 mm outer diameter and 30 mm width (2.165 × 3.74 × 1.181 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 136 kN, C0 156 kN, fatigue load limit Pu 17.6 kN, reference speed 5,600 r/min, limiting speed 6,700 r/min, mass about 850 g. It is an open, separable bearing with a pressed-steel cage.
How does the 33111 bore code work?
The last two digits of 33111 are bore code 11, so 11 × 5 = 55 mm bore. The 95 mm OD and 30 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 33111 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 31 is the ISO 355 series (light wide 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 33111 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 33111 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 33111 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.