6406 bearing: complete specifications & equivalents
The 6406 is a ISO 15 radial bearing sized 30 x 90 x 23 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 30 mm |
| Outer diameter D | 90 mm |
| Width B | 23 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 | 43.6 kN |
| Basic static load rating C0 | 23.6 kN |
| Fatigue load limit Pu | 1 kN |
| Reference speed (thermal) | 18000 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 750 g |
| Manufacturer designation | SKF 6406 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-25 |
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 & 6400-series range
| Bore d | 1.181 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 0.906 in |
| ISO bore code | 06 |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 6400-series | 10 mm |
| Largest outer diameter in 6400-series | 250 mm |
| Width range across 6400-series | 12–58 mm |
| Bore position in 6400-series (smallest first) | 7 of 21 |
| Bore above smallest 6400-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6406-FAG | FAG | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 6406-2RS | GENERIC-ISO | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×90×23 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6406-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 6406-ZZ | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×90×23 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
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 6406 model number is decoded
In the 6400-series (diameter series 4 of ISO 15) the last two digits encode the bore: 6406 carries bore code 06 = 30 mm. Outside diameter 90 mm and width 23 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 30 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
- small gearboxes
- conveyors and drives
- agricultural equipment
- fans and blowers
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- false brinelling from vibration while the shaft is stationary
- fretting corrosion on a loose shaft seat
Selection pitfalls — read before you substitute
- Sizes around 30 mm bore are normally pressed on cold with a sleeve against the inner-ring face; the press force must never route through the outer ring or the balls of 6406.
- The 64xx heavy section at 30 mm bore exists for high radial load at moderate rpm; its 90 mm OD and 23 mm width demand a larger housing, and grease life at motor speeds is short — treat it as a low-speed, high-load choice.
- Storage matters for open bearings: 6406 leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
- Open bearings tolerate the highest speeds in the 6400-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 6406 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.
- Measure the shaft, do not trust the drawing: a 30 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 6406.
- The open 6406 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 6406-2Z (shields) and 6406-2RSH (contact seals), not suffix-free 6406.
- The 43.6/23.6 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 6406 bearing?
A 6406 deep-groove ball bearing has a 30 mm bore, 90 mm outer diameter and 23 mm width (1.181 × 3.543 × 0.906 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
What lubrication does 6406 need?
The open 6406 is lubricated by the application; a NLGI 2 lithium-soap grease filled to roughly 25–35% of the free volume is the common choice, with a defined relubrication interval.
How does the 6406 bore code work?
The last two digits of 6406 are bore code 06, giving 06 × 5 = 30 mm bore. The 90 mm outside diameter and 23 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 6406 mean?
A bare 6406 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.
What is the SKF designation and catalogue data for 6406?
In the SKF Rolling Bearings catalogue this size is listed as 6406 — the open (unsealed) execution, 30×90×23 mm per ISO 15. Quoted values: C 43.6 kN, C0 23.6 kN, Pu 1 kN, limiting speed 11000 r/min, mass 750 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6406.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-25. Read our editorial & correction policy.