33112 bearing: complete specifications & equivalents
The 33112 is a ISO 355 radial bearing sized 60 x 100 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 | 60 mm |
| Outer diameter D | 100 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 | 144 kN |
| Basic static load rating C0 | 170 kN |
| Fatigue load limit Pu | 19.6 kN |
| Reference speed (thermal) | 5300 rpm |
| Limiting speed (mechanical) | 6300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 920 g |
| Manufacturer designation | SKF 33112 |
| 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 | 2.362 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 1.181 in |
| ISO bore code | 12 |
| 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) | 5 of 12 |
| Bore above smallest 33100-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33112 | 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 33112 model number is decoded
For a 60 mm shaft carrying combined load, SKF lists 33112 under catalogue execution SKF 33112: one open single-row tapered roller bearing in the light wide section of the 33100 family.Reading the designation: the leading 3 marks a single-row tapered roller bearing, the 31 is the ISO 355 diameter/width series (light wide section), and the last two digits encode the 60 mm bore; the 100 mm OD and 30 mm width follow the ISO 355 general plan. In SKF suffix language a bare 33112 is the standard execution; B marks a larger contact angle and Q or J2 mark clearance/cage variants, all quoted separately. With C 144 kN and C0 170 kN, the 33112 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 6,300 r/min. Because the contact line is tapered, one 33112 reacts thrust in a single direction; bidirectional shafts need an O or X pair, and a rotating cone on a 60 mm shaft typically takes a k5 seat with an H7 housing bore.
Typical equipment & failure modes
Common applications
- crane sheave and hoist gearboxes
- paper-machine and printing rolls
- construction machinery drives
- marine deck machinery shafts
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
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- brinelling from pressing the cone or cup home through the rollers
Selection pitfalls — read before you substitute
- Mount the 60 mm bore 33112 by induction heating of the cone (max 120 °C — the pressed-steel cage sets the ceiling, not the steel); driving it home through the cup or rollers brinells the tapered raceway.
- The 331 series at 60 mm bore (100×30 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.
- 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 33112 mounting error.
- Setting is a design value, not an assembly feel: excessive preload in the 33112 pair raises operating temperature and can trigger thermal runaway, while too little lets the rollers skid and smear the raceway under light load.
- Catalogue reference speed and limiting speed are different limits: the 5,300 r/min reference is a thermal criterion under load, while the 6,300 r/min limiting value is the mechanical ceiling — observe both.
- The 144/170 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 33112 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 33112 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 33112?
The SKF 33112 is a single-row tapered roller bearing with 60 mm bore, 100 mm outer diameter and 30 mm width (2.362 × 3.937 × 1.181 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 144 kN, C0 170 kN, fatigue load limit Pu 19.6 kN, reference speed 5,300 r/min, limiting speed 6,300 r/min, mass about 920 g. It is an open, separable bearing with a pressed-steel cage.
How does the 33112 bore code work?
The last two digits of 33112 are bore code 12, so 12 × 5 = 60 mm bore. The 100 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 33112 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 33112 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 33112 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 33112 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.