6218-M bearing: complete specifications & equivalents
The 6218-M is a ISO 15 radial bearing sized 90 x 160 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 | 90 mm |
| Outer diameter D | 160 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 101 kN |
| Basic static load rating C0 | 73.5 kN |
| Fatigue load limit Pu | 2.8 kN |
| Reference speed (thermal) | 8500 rpm |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2650 g |
| Manufacturer designation | 6218 M |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); 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 & 6200-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 1.181 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 6200-series | 3 mm |
| Largest outer diameter in 6200-series | 540 mm |
| Width range across 6200-series | 2.5–85 mm |
| Bore position in 6200-series (smallest first) | 27 of 45 |
| Bore above smallest 6200-series size | 87 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6218-RSR | NSK | full Dimensions and internal design equivalent — standard interchange. | NSK counterpart NSK 6218VV on the same 90×160×30 mm envelope with ratings within 10 % — interchange after checking seal, cage and precision details on both pages. |
| 218 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×160×30 mm envelope as SKF 218, but catalogue C/C0 differ (101/73.5 kN vs 112/114 kN) — envelope match only after a load check. |
| 218-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×160×30 mm envelope as SKF 218-2Z, but catalogue C/C0 differ (101/73.5 kN vs 112/114 kN) — envelope match only after a load check. |
| 6218 | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF SKF 6218 (open arrangement) shares the 90×160×30 mm envelope with ratings within 10 % — execution variant of the same size; boundary dimensions interchangeable. |
| 6218-ZZ | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF SKF 6218-2Z (two non-contact shields) shares the 90×160×30 mm envelope with ratings within 10 % — execution variant of the same size; boundary dimensions interchangeable. |
| 6218-2RS | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF SKF 6218-2RS1 (two contact elastomer seals) shares the 90×160×30 mm envelope with ratings within 10 % — execution variant of the same size; boundary dimensions interchangeable. |
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 6218-M model number is decoded
In the 6200-series, the last two digits encode the bore: 6218 carries code 18 = 90 mm (code × 5). The envelope is 90×160×30 mm (3.543×6.299×1.181 in) with a 35.0 mm radial section height, C 101 kN, C0 73.5 kN and Pu 2.8 kN. The open 6218 M carries no shields or seals and relies on application lubrication and external sealing. The M suffix identifies the machined brass cage execution, a separate order number from the pressed-steel version. Limiting speed 5300 r/min, catalogue mass 2650 g.
Typical equipment & failure modes
Common applications
- gearboxes and speed reducers
- centrifugal and positive-displacement pumps
- material-handling equipment
- industrial fans
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- rolling-contact fatigue spalling once the catalogue L10 life is exceeded
- brinelling from static overload or hammer blows during mounting
Selection pitfalls — read before you substitute
- Assign interference to the rotating ring: on a conventional shaft-mounted 90 mm position the inner ring rotates, so use a k5/m6 shaft seat with an H7 housing — reverse the logic if the outer ring rotates.
- At 90 mm bore, C3 clearance is the safe choice when interference fits plus temperature rise consume the CN clearance; a hot tight bearing with no residual clearance fails fast.
- The M suffix on 6218-M denotes a machined brass cage: it is the choice for high speeds, marginal lubrication and shock/vibration duty, and it is temperature-tolerant where polymer cages are not — the 2650 g quoted mass includes the heavier cage.
- Open 6218-M needs external sealing at the arrangement level; in dusty housings its life depends entirely on those external seals and the regreasing schedule.
- Plan a relubrication interval for 6218-M; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- At 90 mm bore, C3 clearance is the safe choice when interference fits plus temperature rise consume the CN clearance; a hot tight bearing with no residual clearance fails fast.
Frequently asked questions
What are the dimensions of 6218-M?
The SKF 6218 M measures 90 mm bore × 160 mm OD × 30 mm width (3.543 × 6.299 × 1.181 in), mass about 2650 g. It is open, with no shields or seals.
How does the bore code in 6218 work?
The final two digits of 6218 are bore code 18, multiplied by 5 to give 90 mm.
What load can 6218-M take?
Catalogue values for 6218 M: dynamic C 101 kN, static C0 73.5 kN, fatigue limit Pu 2.8 kN. Use C in life calculation and C0 for static checks at 90 mm bore.
What is the speed rating of 6218-M?
SKF lists a 8500 r/min thermal reference speed and a 5300 r/min mechanical limiting speed for 6218 M; real limits also depend on lubrication and fits.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.