30240-DF bearing: complete specifications & equivalents
The 30240-DF is a ISO 355 radial bearing sized 200 x 360 x 128 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 200 mm |
| Outer diameter D | 360 mm |
| Width B | 128 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 1448 kN |
| Basic static load rating C0 | 2240 kN |
| Fatigue load limit Pu | 212 kN |
| Reference speed (thermal) | 1000 rpm |
| Limiting speed (mechanical) | 1700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 52000 g |
| Manufacturer designation | SKF 30240/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 | 7.874 in |
|---|---|
| Outer diameter D | 14.173 in |
| Width B | 5.039 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 80 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) | 27 of 35 |
| Bore above smallest matched-df-series size | 175 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30240 | 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 30240-DF model number is decoded
The code breaks down as base bearing 30240 plus matched-set suffix /DF: two bearings of the 200 mm bore size, paired face-to-face (X) matched pair, with the 128 mm overall width spanning the whole arrangement. Face-to-face matching puts the small rib ends outward, so the pressure cones cross inside the pair; 30240-DF therefore runs cooler where the shaft expands axially, at the price of lower moment stiffness than an O-arrangement of the same 200 mm bore. Speed planning for the set uses the catalogue pair values: 1,000 r/min thermal reference and 1,700 r/min mechanical limiting speed — a matched pair runs warmer than one bearing because two roller sets share the 128 mm space. Journal and housing interface: the 200 mm bore takes a m6 shaft seat and the 360 mm outside diameter pairs with an H7 housing bore; the 128 mm width defines shoulder depth and the 52000 g mass is the dead load in thermal-growth calculations. When a matched /DF set like 30240-DF is replaced, replace the whole set: mixing a new bearing with a worn partner from the old set leaves the clearance and load sharing of the pair undefined. Do not separate 30240-DF into single-bearing service stock — as individual bearings the components are not interchangeable with catalogue single-row executions because the rings are ground for the set.In SKF catalogue PUB BU/P1 17000, 30240-DF appears as SKF 30240/DF: a matched face-to-face (X) matched pair pair for a 200 mm shaft, rated as a set at C 1448 kN and C0 2240 kN.
Typical equipment & failure modes
Common applications
- large industrial mixer shafts
- offshore winch and drawworks drums
- rolling-mill roll-neck bearings
- rolling-mill roll-neck bearings
Known failure patterns
- false brinelling on idle paired sets exposed to machine vibration
- 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
- hard-particle indentation of the tapered raceway in unfiltered oil
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- O and X arrangements are not interchangeable by turning the set around: 30240-DF in face-to-face (X) matched pair arrangement has its load-line geometry fixed — specify the arrangement from the shaft thermal and stiffness analysis.
- Setting is built into 30240-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.
- Replace 30240-DF as a complete set: pairing a new bearing with a worn partner leaves the clearance undefined even when the designation matches.
- The 1448/2240 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 30240/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 30240-DF?
The SKF 30240/DF is a matched pair of single-row tapered roller bearings in face-to-face (X) matched pair arrangement with 200 mm bore, 360 mm outer diameter and 128 mm overall width (7.874 × 14.173 × 5.039 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 1448 kN, C0 2240 kN, fatigue load limit Pu 212 kN, reference speed 1,000 r/min, limiting speed 1,700 r/min, mass about 52.00 kg.
What does the /DF suffix on 30240-DF mean?
The base 30240 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 30240-DF for one bearing or the pair?
They are for the complete matched pair: C 1448 kN dynamic and C0 2240 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 30240 table values.
Can 30240-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 200 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 200 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.