32256-DF bearing: complete specifications & equivalents
The 32256-DF is a ISO 355 radial bearing sized 280 x 500 x 274 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 280 mm |
| Outer diameter D | 500 mm |
| Width B | 274 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 2410 kN |
| Basic static load rating C0 | 7800 kN |
| Fatigue load limit Pu | 620 kN |
| Reference speed (thermal) | 700 rpm |
| Limiting speed (mechanical) | 1200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 226000 g |
| Manufacturer designation | SKF 32256/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 | 11.024 in |
|---|---|
| Outer diameter D | 19.685 in |
| Width B | 10.787 in |
| ISO bore code | 56 |
| Radial section height (D−d)/2 | 110 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) | 31 of 35 |
| Bore above smallest matched-df-series size | 255 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32256 | 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 32256-DF model number is decoded
Digit by digit, 32256-DF reads as the ISO 355 base bearing 32256 supplied as a face-to-face (X) matched pair matched pair (/DF); the 280 mm bore and 500 mm OD are per-bearing, the 274 mm width is for the set. Face-to-face matching puts the small rib ends outward, so the pressure cones cross inside the pair; 32256-DF therefore runs cooler where the shaft expands axially, at the price of lower moment stiffness than an O-arrangement of the same 280 mm bore. Selection arithmetic: the catalogue C 2410 kN and C0 7800 kN are ratings of the complete pair, not of one bearing — never halve them back to a single-row figure when checking L10 life, and use the pair Pu 620 kN as the fatigue floor. Operating context for the 280 mm bore: a shaft of this diameter typically runs in the xl-bore band of industrial duty, and the 500 mm OD places the housing shoulder near 508 mm outer abutment. Mounting order matters for 32256-DF: seat the first bearing, fit the ground spacer, then the second bearing, and clamp axially as a unit — the 274 mm catalogue width is the assembled result and the gauge for correct assembly. Lubrication for the pair should be sized against the combined 274 mm width and 226000 g mass: two roller sets sweep twice the contact area of a single bearing of the same bore.32256-DF (SKF 32256/DF) is the face-to-face (X) matched pair matched-set choice for a 280 mm shaft: a pair of tapered roller bearings whose combined envelope is 500×274 mm, delivered ready to mount with controlled internal clearance.
Typical equipment & failure modes
Common applications
- wind-turbine main shafts
- marine propulsion gearboxes
- large industrial mixer shafts
- large industrial mixer shafts
Known failure patterns
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- roller large-end smearing against the cone rib after EP lubricant film failure
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- grease degradation after long shelf storage without rotation or re-greasing
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- Setting is built into 32256-DF; the classic field error is re-adjusting a matched pair as if it were two loose single bearings, which destroys the /DF clearance class.
- Clamp the 32256-DF pair axially through the cones, never through the rollers; pressing force across the roller complement brinells the raceways of both bearings at once.
- Setting is built into 32256-DF; the classic field error is re-adjusting a matched pair as if it were two loose single bearings, which destroys the /DF clearance class.
- The 2410/7800 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 32256/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 32256-DF?
The SKF 32256/DF is a matched pair of single-row tapered roller bearings in face-to-face (X) matched pair arrangement with 280 mm bore, 500 mm outer diameter and 274 mm overall width (11.024 × 19.685 × 10.787 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 2410 kN, C0 7800 kN, fatigue load limit Pu 620 kN, reference speed 700 r/min, limiting speed 1,200 r/min, mass about 226.00 kg.
What does the /DF suffix on 32256-DF mean?
The base 32256 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 32256-DF for one bearing or the pair?
They are for the complete matched pair: C 2410 kN dynamic and C0 7800 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 32256 table values.
Can 32256-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 280 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 280 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.