25577-25523 bearing: complete specifications & equivalents
The 25577-25523 is a ISO 355 radial bearing sized 42.875 x 82.931 x 26.988 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 42.875 mm |
| Outer diameter D | 82.931 mm |
| Width B | 26.988 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 99.1 kN |
| Basic static load rating C0 | 106 kN |
| Fatigue load limit Pu | 12 kN |
| Reference speed (thermal) | 6700 rpm |
| Limiting speed (mechanical) | 8000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 630 g |
| Manufacturer designation | SKF 25577/25523 |
| 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 & 25500-series range
| Bore d | 1.688 in |
|---|---|
| Outer diameter D | 3.265 in |
| Width B | 1.063 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 20 mm |
| Smallest bore in 25500-series | 38.1 mm |
| Largest outer diameter in 25500-series | 83.058 mm |
| Width range across 25500-series | 23.812–26.988 mm |
| Bore position in 25500-series (smallest first) | 2 of 4 |
| Bore above smallest 25500-series size | 4.774999999999999 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 25577-25520-NTN | NTN | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue. |
| 25577-25523 | 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 25577-25523 model number is decoded
For a 42.875 mm shaft carrying combined load, SKF lists 25577 under catalogue execution SKF 25577/25523: one open single-row tapered roller bearing in the inch 25500-series.On the SKF nameplate, 25577 denotes a matched cone-and-cup pair: the designation is not a single number but a cone reference and cup reference joined by a slash, with the 25500-series marking the dimensional series. SKF lists the plain number as the basic execution; letter suffixes such as B denote a steeper contact angle and are different order numbers. Speed planning uses two different ceilings: 6,700 r/min thermal reference and 8,000 r/min mechanical limiting speed. Mounting practice for 25577: the rotating cone takes the interference fit (k5 on a 42.875 mm shaft), the cup slides for axial location, and reversing-thrust duty demands a paired O/X set rather than one bearing. Operating context for the 42.875 mm bore: a shaft of this diameter in the medium-bore band typically runs between 34300 and 51450 r/min in real machinery, and the 82.931 mm outside diameter places the housing shoulder at 91 mm outer abutment; the 26.988 mm width and 630 g mass together set the shaft critical speed and the housing resonance check for this 25500-series envelope. A single-row inch tapered bearing is quoted as a cone/cup pair because the boundary dimensions belong to the combination, not to either half alone: in 25577 the 25577 cone contributes the 42.875 mm bore and roller set, the 25523 cup contributes the 82.931 mm OD raceway, and the assembled 26.988 mm width is the catalogue value.
Typical equipment & failure modes
Common applications
- industrial gearbox shafts and reducers
- differential and pinion drives
- pump and compressor shafts
- industrial gearbox shafts and reducers
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
- roller large-end smearing against the cone rib after EP lubricant film failure
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- brinelling from pressing the cone or cup home through the rollers
Selection pitfalls — read before you substitute
- On this 42.875 mm bore, interference and temperature rise consume clearance inside a preloaded pair; calculate the residual clearance after mounting and at operating temperature — an over-tight 25577 pair heats, loses setting control and smears the roller-rib contact.
- The 25500-series inch series at 42.875 mm bore (82.931×26.988 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 25577 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- A single 25577 cannot locate the shaft axially in both directions; mounting it singly on a reversing-thrust shaft leaves one direction uncontrolled — always use an O or X matched pair for bidirectional location.
- Shaft and housing fillets must clear the bearing chamfer so the 26.988 mm-wide cup seats square; use an undercut or withdrawal groove rather than an oversized radius that locks on the ring face.
- The 99.1/106 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 25577 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 25577/25523 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 25577?
The SKF 25577/25523 is a single-row tapered roller bearing with 42.875 mm bore, 82.931 mm outer diameter and 26.988 mm width (1.688 × 3.265 × 1.063 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 99.1 kN, C0 106 kN, fatigue load limit Pu 12 kN, reference speed 6,700 r/min, limiting speed 8,000 r/min, mass about 630 g. It is an open, separable bearing with a pressed-steel cage.
How does the 25577 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 25500-series code marks the dimensional series. The metric dimensions 42.875×82.931×26.988 mm are the converted equivalents of the original inch boundary dimensions.
What do the cone and cup numbers in 25577 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 (25500-series) groups sizes that share the same boundary-dimension plan.
Can a single 25577 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 25577 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 25577 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
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.