7408 bearing: complete specifications & equivalents
The 7408 is a ISO 15 radial bearing sized 40 x 110 x 27 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 40 mm |
| Outer diameter D | 110 mm |
| Width B | 27 mm |
| Seal / shield | open |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | brass |
| Operating temperature | -40 to +150 °C |
| Mass (geometry estimate) | 1136 g |
| Standard | ISO 15 |
| Catalog version | iso15-ed4-geometry |
| Last verified | 2026-09-24 |
Source: ISO 15 boundary-dimensions standard · extracted 2026-09-24
Standard-interchange bearing: dimensions per ISO 15; CN clearance, P0 tolerance and a stamped-steel cage are catalogue defaults unless the supplier states otherwise, and mass is a geometry-derived estimate. Brand catalogue load ratings and limiting speeds for 7408 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 7400-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.063 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 7400-series | 20 mm |
| Largest outer diameter in 7400-series | 180 mm |
| Width range across 7400-series | 19–42 mm |
| Bore position in 7400-series (smallest first) | 5 of 11 |
| Bore above smallest 7400-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7408 | 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 7408 model number is decoded
In the 7400-series (ISO 15 diameter series 4) the last two digits encode the bore: 7408 carries bore code 08 = 40 mm. Outside diameter 110 mm and width 27 mm come from the ISO 15 boundary-dimensions general plan, shared with the 6408 deep-groove envelope. The '7' prefix marks a single-row angular-contact design with an asymmetric raceway and a nominal 40° contact angle (suffix C); a higher-angle variant carries more axial load, a 25° (E / A5) variant runs faster. For combined radial and axial load with a rotating inner ring on a 40 mm shaft, specify a k5 shaft seat with an H7 housing bore — verify against the load direction and magnitude, and pair two units (DB or DF) for bidirectional thrust.
Typical equipment & failure modes
Common applications
- servo and stepper drives
- gear reducers
- electric motor shafts
- conveyor head pulleys
Known failure patterns
- preload loss after a paired set runs loose, letting the balls skid and smear the raceway
- raceway smearing under marginal lubrication at start-up before oil climb reaches the contact
- cage fracture from operation beyond the limiting speed with inadequate lubricant
- fretting corrosion on a loose shaft seat that lets the inner ring creep
Selection pitfalls — read before you substitute
- At a 40 mm bore, shaft-seat finish and runout (target Ra ≤ 0.8 µm) govern angular-contact noise; a rough or out-of-round seat shows up as spindle runout before it shows as failure.
- The 74xx heavy section at 40 mm bore (110 mm OD) is built for high combined load at lower speed; specifying it in a high-rpm spindle gives excess heat and short grease life — use 72/73 there.
- Preload class matters: a 7408 in a DB pair is supplied as preload class light (L) for speed or heavy (H) for rigidity; mixing unmarked bearings in a pair gives uneven preload and short life.
- Mounting direction is fixed by the asymmetric raceway — the marked side faces the axial load; installing 7408 backwards loads the low shoulder and displaces the balls out of the raceway.
Frequently asked questions
What are the dimensions of a 7408 angular-contact bearing?
A 7408 single-row angular-contact ball bearing has a 40 mm bore, 110 mm outer diameter and 27 mm width (1.575 × 4.331 × 1.063 in), per ISO 15 boundary dimensions. It is an open bearing with a nominal 40° contact angle. Geometry-based estimated mass is about 1136 g for a brass-cage unit; catalogue masses vary with cage and ball complement.
How does the 7408 bore code work?
The last two digits of 7408 are bore code 08, giving 08 × 5 = 40 mm bore. The 110 mm outside diameter and 27 mm width follow the ISO 15 diameter series, shared with the 6408 deep-groove envelope.
What is the contact angle of 7408?
The nominal contact angle is 40° (suffix C): a higher angle carries more axial load but limits speed. A 25° (suffix E or A5) variant runs faster and is preferred for high-speed spindles; a 15° (suffix C7) version exists for very-high-speed duty. Confirm the angle and ball complement in the supplier catalogue.
Can a single 7408 take axial load in both directions?
No. A single-row angular-contact bearing carries axial load in one direction only. For bidirectional thrust, mount a matched pair — DB (back-to-back) for a rigid, moment-resisting arrangement with preload class light (L) for speed or heavy (H) for stiffness, DF (face-to-face) for thermal expansion tolerance, or DT (tandem) to share one-direction load.
How does 7408 compare with a deep-groove 6408?
Both share the 40×110×27 mm ISO 15 envelope (35.0 mm radial section), but the angular-contact 7408 has an asymmetric raceway and 40° contact angle: it carries higher combined axial+radial load and runs with controlled preload, but is slower, noisier and needs pairing — it is not a drop-in replacement for a deep-groove 6408.
Reviewed & verified by the MPN Base engineering desk against source catalog iso15-ed4-geometry on 2026-09-24. Read our editorial & correction policy.