33122-DF bearing: complete specifications & equivalents
The 33122-DF is a ISO 355 radial bearing sized 110 x 180 x 112 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 110 mm |
| Outer diameter D | 180 mm |
| Width B | 112 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 781 kN |
| Basic static load rating C0 | 1250 kN |
| Fatigue load limit Pu | 132 kN |
| Reference speed (thermal) | 2200 rpm |
| Limiting speed (mechanical) | 3400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 11500 g |
| Manufacturer designation | SKF 33122/DF |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants |
| Last verified | 2026-09-29 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants) · extracted 2026-09-29
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants); 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 & matched-df-series range
| Bore d | 4.331 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 4.409 in |
| ISO bore code | 22 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in matched-df-series | 25 mm |
| Largest outer diameter in matched-df-series | 540 mm |
| Width range across matched-df-series | 34.5–280 mm |
| Bore position in matched-df-series (smallest first) | 18 of 35 |
| Bore above smallest matched-df-series size | 85 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33122 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 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 33122-DF model number is decoded
Reading the designation: 33122 is the ISO 355 single-row base bearing (110 mm bore), and the suffix /DF marks the matched-set execution — arrangement, spacer grinding and factory clearance class. The pair envelope is 110×180×112 mm; the width covers both bearings of the set. In the face-to-face (X) arrangement the load lines of the two bearings converge toward the shaft axis: the set tolerates shaft deflection and thermal growth better than a back-to-back pair, but is less stiff against overturning moments. The 112 mm overall width of 33122-DF is the axial space the pair occupies. The C0/C balance of the pair is about 1.60; combined with the 132 kN fatigue limit this frames a set sized for reversing combined load on a 110 mm shaft rather than for pure radial duty. Material and manufacturing detail: the 11500 g catalogue mass reflects through-hardened bearing steel machined to the listed envelope; ring roundness and width tolerance keep the mounted-setting scatter inside the catalogue class. Inspection shorthand: at overhaul, mark both bearings and the spacer of 33122-DF before disassembly — the set is a matched system, and re-assembling with one component reversed changes the factory setting. Lubrication for the pair should be sized against the combined 112 mm width and 11500 g mass: two roller sets sweep twice the contact area of a single bearing of the same bore.For a 110 mm shaft carrying reversing axial load, SKF lists 33122-DF under catalogue execution SKF 33122/DF: a factory-matched face-to-face (X) matched pair tapered-roller pair, set and measured as one unit.
Typical equipment & failure modes
Common applications
- rolling-mill auxiliary drives
- crane sheave and hoist gearboxes
- paper-machine and printing rolls
- paper-machine and printing rolls
Known failure patterns
- 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
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- fretting corrosion on a loose rotating shaft seat
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- Replace 33122-DF as a complete set: pairing a new bearing with a worn partner leaves the clearance undefined even when the designation matches.
- Spacer faces must stay parallel within the set's own tolerance; a tilted spacer in 33122-DF concentrates reversing thrust on one bearing and shows up as one-sided raceway wear.
- Clamp the 33122-DF pair axially through the cones, never through the rollers; pressing force across the roller complement brinells the raceways of both bearings at once.
- The 781/1250 kN ratings are SKF catalogue 17000 values for this 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.
- Quote the full SKF 33122/DF designation when purchasing — base-number-only orders are ambiguous across executions and variants.
Frequently asked questions
What are the dimensions and catalogue data of 33122-DF?
The SKF 33122/DF is a matched pair of single-row tapered roller bearings in face-to-face (X) matched pair arrangement with 110 mm bore, 180 mm outer diameter and 112 mm overall width (4.331 × 7.087 × 4.409 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 781 kN, C0 1250 kN, fatigue load limit Pu 132 kN, reference speed 2,200 r/min, limiting speed 3,400 r/min, mass about 11.50 kg.
What does the /DF suffix on 33122-DF mean?
The base 33122 is the ISO 355 single-row bearing; the /DF suffix marks the matched-set execution — the arrangement (face-to-face (X)), the ground spacer and the factory-set axial clearance class. A matched set cannot be assembled from loose single bearings; quote the full designation when ordering.
Are the C and C0 ratings of 33122-DF for one bearing or the pair?
They are for the complete matched pair: C 781 kN dynamic and C0 1250 kN static already include load sharing between the two bearings. Do not halve them for single-bearing checks, and do not compare them directly with the single-row 33122 table values.
Can 33122-DF be adjusted like two loose tapered bearings?
No — the axial clearance is set at the factory by selective spacer grinding. Mounting work is limited to clean seats, correct fits (m6 on a rotating 110 mm shaft) and axial clamping through the cones; re-setting in the field destroys the matched clearance class.
When should a face-to-face (X) matched set be chosen?
Choose the face-to-face (X) set where the shaft grows thermally or alignment is imperfect — the converging load lines tolerate deflection. It is the default choice for wheel hubs and general gearbox shafts at the 110 mm bore.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants on 2026-09-29. Read our editorial & correction policy.