6218 bearing: complete specifications & equivalents
The 6218 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 |
|---|---|
| Bore diameter d | 90 mm |
| Outer diameter D | 160 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| 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 +150 °C |
| Mass | 2200 g |
| Manufacturer designation | SKF 6218 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-24 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
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 | 10 mm |
| Largest outer diameter in 6200-series | 400 mm |
| Width range across 6200-series | 9–65 mm |
| Bore position in 6200-series (smallest first) | 19 of 33 |
| Bore above smallest 6200-series size | 80 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6218 | 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 6218 model number is decoded
In the 6200-series (ISO 15 diameter series 2) the last two digits encode the bore: 6218 carries bore code 18 = 90 mm. Outside diameter 160 mm and width 30 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 90 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. In the SKF catalogue this open execution carries the bare designation; protected variants are ordered separately as -2Z and -2RSH.
Typical equipment & failure modes
Common applications
- industrial fans and blowers
- hoists and winches
- heavy conveyors
- pulp and paper machinery
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- fretting corrosion on a loose shaft seat
- cage damage from operation beyond the limiting speed
Selection pitfalls — read before you substitute
- Mount this 90 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 62xx light series is the default general-purpose section at 90 mm bore; before upgrading to a 6318 for extra capacity, confirm the housing accepts a 160 mm OD and 30 mm width — it is not a drop-in swap.
- The open 6218 has no lubricant retention: grease escapes and contaminants migrate straight into the 90×160×30 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 6200-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 6218 units.
- Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
- The open 6218 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 6218-2Z (shields) and 6218-2RSH (contact seals), not suffix-free 6218.
- The 101/73.5 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 6218 bearing?
A 6218 deep-groove ball bearing has a 90 mm bore, 160 mm outer diameter and 30 mm width (3.543 × 6.299 × 1.181 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields. Geometry-based estimated mass is about 2104 g for a steel-cage unit; catalogue masses vary slightly with seal and cage design.
How does the 6218 bore code work?
The last two digits of 6218 are bore code 18, giving 18 × 5 = 90 mm bore. The 160 mm outside diameter and 30 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 6218 mean?
A bare 6218 designation means open: no shields or seals, normal CN radial clearance and P0 normal tolerance unless further suffixes are ordered. The application must supply and retain the lubrication.
How does the 6200 compare with other series at the same 90 mm bore?
The '2' is the light diameter series: 160×30 mm with a 35.0 mm radial section at 90 mm bore. A 6318 on the same bore is larger and higher-rated; a 6018 is smaller and lower-rated.
What is the SKF designation and catalogue data for 6218?
In the SKF Rolling Bearings catalogue this size is listed as 6218 — the open (unsealed) execution, 90×160×30 mm per ISO 15. Quoted values: C 101 kN, C0 73.5 kN, Pu 2.8 kN, limiting speed 5300 r/min, mass 2200 g. Brand suffixes (2Z, 2RSH) differ from the industry-neutral spelling 6218.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-24. Read our editorial & correction policy.