90381-90744 bearing: complete specifications & equivalents
The 90381-90744 is a ISO 355 radial bearing sized 96.838 x 188.912 x 50.8 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 96.838 mm |
| Outer diameter D | 188.912 mm |
| Width B | 50.8 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 348 kN |
| Basic static load rating C0 | 375 kN |
| Fatigue load limit Pu | 41.5 kN |
| Reference speed (thermal) | 2600 rpm |
| Limiting speed (mechanical) | 3400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5750 g |
| Manufacturer designation | SKF 90381/90744 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB |
| Last verified | 2026-09-28 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB) · extracted 2026-09-28
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB); 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 & 90300-series range
| Bore d | 3.813 in |
|---|---|
| Outer diameter D | 7.437 in |
| Width B | 2 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 46 mm |
| Smallest bore in 90300-series | 96.838 mm |
| Largest outer diameter in 90300-series | 188.912 mm |
| Width range across 90300-series | 50.8–50.8 mm |
| Bore position in 90300-series (smallest first) | 1 of 1 |
| Bore above smallest 90300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 90381-90744-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 96.838×188.912×50.8 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 90381-90744 | Timken | full Dimensions and internal design equivalent — standard interchange. | Same inch-series cone/cup boundary envelope (d/D/T); load ratings and speed limits are brand-specific and may differ. |
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 90381-90744 model number is decoded
Reading the designation: 90381 follows the Timken-style inch convention — the cone (inner ring with rollers) and cup (outer ring) are quoted as a pair separated by a slash, and the 90300-series code identifies the dimensional series. The 96.838 mm bore, 188.912 mm OD and 50.8 mm width are the metric equivalents of the inch boundary dimensions. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. Selection arithmetic: the C0/C ratio is about 1.08 (static 375 kN against dynamic 348 kN), typical of a tapered roller sized for axial capacity, and the 41.5 kN fatigue load limit Pu is the equivalent-load floor used in the life calculation. For a 96.838 mm shaft the usual cone seat is k5 with an H7 housing when the inner ring rotates; arrange two 90381 bearings as a set for two-direction location and set clearance from the load diagram, never from assembly feel. Operating context for the 96.838 mm bore: a shaft of this diameter in the large-bore band typically runs between 77470 and 116206 r/min in real machinery, and the 188.912 mm outside diameter places the housing shoulder at 197 mm outer abutment; the 50.8 mm width and 5750 g mass together set the shaft critical speed and the housing resonance check for this 90300-series envelope. Cone versus cup responsibility in 90381: the 90381 cone carries the 96.838 mm bore, rollers and pressed-steel cage; the 90744 cup carries the 188.912 mm OD raceway, the roller-seating rib and the outer press-fit surface. The two references are not interchangeable halves.In SKF catalogue PUB BU/P1 17000, 90381 appears as SKF 90381/90744: an open, single-row tapered roller bearing in the 90300-series, supplied with a pressed-steel cage as standard.
Typical equipment & failure modes
Common applications
- marine deck machinery shafts
- heavy industrial gearboxes and speed reducers
- large process pump and compressor shafts
- large process pump and compressor shafts
Known failure patterns
- cup or cone misalignment when the separable rings are not seated square during mounting
- loose cup rotation in the housing when the specified press fit is not achieved
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- false brinelling on idle paired sets exposed to machine vibration
- 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
Selection pitfalls — read before you substitute
- Mount the 96.838 mm bore 90381 by induction heating of the cone (max 120 °C — the pressed-steel cage sets the ceiling, not the steel); driving it home through the cup or rollers brinells the tapered raceway.
- The 90300-series inch series at 96.838 mm bore (188.912×50.8 mm) follows the Timken cone/cup convention; substitutions must match both the cone and cup reference exactly — interchanging with another series or a metric 3xxxx bearing of the same bore changes OD, width and contact angle, so re-run the pair setting and shoulder-diameter checks before swapping.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of 90381 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of 90381 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- Never press both rings through the wrong element during fitting: force for an interference shaft seat goes through the cone only, or brinell marks on the 188.912 mm cup race release as noise within the first running hours.
- The 348/375 kN ratings are SKF catalogue 17000 values for the basic 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 and re-verify for critical drives.
- SKF lists several executions of 90381 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 90381/90744 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
How does the 90381 inch-series designation work?
Inch-series tapered roller bearings use a Timken-style cone/cup convention: the number before the slash identifies the cone (inner ring with roller and cage assembly), the number after the slash identifies the cup (outer ring), and the 90300-series code marks the dimensional series. The metric dimensions 96.838×188.912×50.8 mm are the converted equivalents of the original inch boundary dimensions.
What do the cone and cup numbers in 90381 mean?
The cone number (before the slash) identifies the inner ring, rollers and cage; the cup number (after the slash) identifies the outer ring. Both are quoted together because a single-row tapered roller bearing is a matched separable pair — the cone and cup are ground to work together and are not interchangeable with arbitrary other parts. The series prefix (90300-series) groups sizes that share the same boundary-dimension plan.
Can a single 90381 take axial load in both directions?
No — one single-row tapered roller bearing reacts thrust in one direction only, and under radial load its contact angle induces an axial force. Use two bearings as a matched pair: O (back-to-back) for a rigid, moment-resisting arrangement, X (face-to-face) where thermal expansion must be tolerated, or tandem where one-direction thrust is shared.
How does 90381 compare with a ball bearing of the same bore?
A tapered roller bearing has line contact and a steep contact angle: much higher combined axial-plus-radial capacity and shock resistance than a ball bearing of the same bore, at the cost of speed, one-direction thrust, mandatory pairing for reversing loads and a minimum axial load requirement. A ball bearing cannot be dropped into a combined-load 90381 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
What shaft and housing fits suit 90381?
For a rotating shaft under normal load, seat the cone on a k5 shaft fit; the cup is usually a loose-to-transition fit in the housing so it can creep slightly and distribute wear. Chamfer and shoulder diameters must clear the bearing rings so the 50.8 mm-wide cup seats square; the mounting setting (end play or preload) is set by the axial position of the cup relative to the cone.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB on 2026-09-28. Read our editorial & correction policy.