30218-DF bearing: complete specifications & equivalents
The 30218-DF is a ISO 355 radial bearing sized 90 x 160 x 65 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 90 mm |
| Outer diameter D | 160 mm |
| Width B | 65 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 411 kN |
| Basic static load rating C0 | 490 kN |
| Fatigue load limit Pu | 57 kN |
| Reference speed (thermal) | 2800 rpm |
| Limiting speed (mechanical) | 4000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5200 g |
| Manufacturer designation | SKF 30218/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 | 3.543 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 2.559 in |
| ISO bore code | 18 |
| 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) | 14 of 35 |
| Bore above smallest matched-df-series size | 65 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30218 | 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 30218-DF model number is decoded
30218-DF (SKF 30218/DF) is the face-to-face (X) matched pair matched-set choice for a 90 mm shaft: a pair of tapered roller bearings whose combined envelope is 160×65 mm, delivered ready to mount with controlled internal clearance.Reading the designation: 30218 is the ISO 355 single-row base bearing (90 mm bore), and the suffix /DF marks the matched-set execution — arrangement, spacer grinding and factory clearance class. The pair envelope is 90×160×65 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 65 mm overall width of 30218-DF is the axial space the pair occupies. Catalogue mass 5200 g covers both bearings and the ground spacer of 30218-DF; keep the set complete — substituting one bearing or a non-ground spacer destroys the factory clearance. Dimensional interchange map: within its boundary plan the 90×160×65 mm envelope of 30218-DF is fixed, so shoulder, spacer and seal drawings can be dimensioned straight from the catalogue table. Setting note for 30218-DF: the axial clearance is set at the factory by selective spacer grinding for the /DF execution; in service, re-checking end play after the first thermal cycle catches seating relaxation before it becomes roller skid. Do not separate 30218-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.
Typical equipment & failure modes
Common applications
- construction machinery drives
- marine deck machinery shafts
- heavy industrial gearboxes and speed reducers
- construction machinery drives
Known failure patterns
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- rib-roller contact scoring from loss of the EP additive film
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- Spacer faces must stay parallel within the set's own tolerance; a tilted spacer in 30218-DF concentrates reversing thrust on one bearing and shows up as one-sided raceway wear.
- Spacer faces must stay parallel within the set's own tolerance; a tilted spacer in 30218-DF concentrates reversing thrust on one bearing and shows up as one-sided raceway wear.
- Clamp the 30218-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 411/490 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 30218/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 30218-DF?
The SKF 30218/DF is a matched pair of single-row tapered roller bearings in face-to-face (X) matched pair arrangement with 90 mm bore, 160 mm outer diameter and 65 mm overall width (3.543 × 6.299 × 2.559 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 411 kN, C0 490 kN, fatigue load limit Pu 57 kN, reference speed 2,800 r/min, limiting speed 4,000 r/min, mass about 5.20 kg.
What does the /DF suffix on 30218-DF mean?
The base 30218 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 30218-DF for one bearing or the pair?
They are for the complete matched pair: C 411 kN dynamic and C0 490 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 30218 table values.
Can 30218-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 (k5 on a rotating 90 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 90 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.