24780-24720 bearing: complete specifications & equivalents
The 24780-24720 is a ISO 355 radial bearing sized 41.275 x 76.2 x 22.225 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 41.275 mm |
| Outer diameter D | 76.2 mm |
| Width B | 22.225 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 84.2 kN |
| Basic static load rating C0 | 86.5 kN |
| Fatigue load limit Pu | 9.65 kN |
| Reference speed (thermal) | 7000 rpm |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 440 g |
| Manufacturer designation | SKF 24780/24720 |
| 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 & 24700-series range
| Bore d | 1.625 in |
|---|---|
| Outer diameter D | 3 in |
| Width B | 0.875 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 17.5 mm |
| Smallest bore in 24700-series | 41.275 mm |
| Largest outer diameter in 24700-series | 76.2 mm |
| Width range across 24700-series | 22.225–22.225 mm |
| Bore position in 24700-series (smallest first) | 1 of 1 |
| Bore above smallest 24700-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 24780-24720-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 41.275×76.2×22.225 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 24780-24720 | 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 24780-24720 model number is decoded
Two catalogue entries share the 24780 cone but use different cups; this one, 24780, takes the 24720 cup and is ground for the resulting 76.2 mm OD / 22.225 mm width envelope. Selecting a sibling cup produces a different boundary plan and a different order number, so the full designation is required at purchase.SKF 24780 (SKF 24780/24720) is the 24700-series tapered roller choice for a 41.275 mm shaft — one row of tapered rollers on an asymmetric raceway inside the 76.2×22.225 mm envelope.Digit by digit, 24780 reads as cone reference / cup reference in the 24700-series inch series; the 41.275 mm bore, 76.2 mm OD and 22.225 mm width are the metric equivalents of the original inch boundary values. In SKF suffix language a bare 24780 is the standard execution; B marks a larger contact angle and Q or J2 mark clearance/cage variants, all quoted separately. The 9.65 kN Pu figure feeds the adjusted-life equation at contaminated or partial-film conditions, and the 1.03 C0/C balance shows this execution is tuned to thrust-heavy combined loads rather than pure radial running. Specify pairs rather than single units wherever thrust reverses: the tapered contact of 24780 generates an induced axial load under radial force, and an unpaired bearing on a reversing shaft will run slack and fret its seat. Material and manufacturing detail: the 440 g catalogue mass reflects through-hardened bearing steel (density ~7.85 g/cm³) machined to the 24700 ISO envelope, with the pressed-steel cage contributing roughly 13 g of the total; the 41.275 mm bore is ground to IT5 roundness and the 76.2 mm OD to IT5 cylindricity, and the 22.225 mm width tolerance keeps the pair-setting scatter within the ISO preload class.
Typical equipment & failure modes
Common applications
- axle-boxes in material-handling equipment
- automotive and light-truck wheel hubs
- industrial gearbox shafts and reducers
- machine-tool spindles
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
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- On this 41.275 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 24780 pair heats, loses setting control and smears the roller-rib contact.
- The 24700-series inch series at 41.275 mm bore (76.2×22.225 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 24780 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- Setting is a design value, not an assembly feel: excessive preload in the 24780 pair raises operating temperature and can trigger thermal runaway, while too little lets the rollers skid and smear the raceway under light load.
- Catalogue reference speed and limiting speed are different limits: the 7,000 r/min reference is a thermal criterion under load, while the 9,000 r/min limiting value is the mechanical ceiling — observe both.
- The 84.2/86.5 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 24780 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 24780/24720 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
Is 24780 interchangeable with other brands?
Inch-series tapered roller bearings follow a long-standing industry boundary plan, so cones and cups of the same basic number are generally dimensionally interchangeable across manufacturers. However, internal geometry, cage design and load ratings differ by brand, so for paired or precision applications keep both halves of the set from one manufacturer — or re-verify ratings and setting when mixing.
What are the dimensions and catalogue data of 24780?
The SKF 24780/24720 is a single-row tapered roller bearing with 41.275 mm bore, 76.2 mm outer diameter and 22.225 mm width (1.625 × 3 × 0.875 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 84.2 kN, C0 86.5 kN, fatigue load limit Pu 9.65 kN, reference speed 7,000 r/min, limiting speed 9,000 r/min, mass about 440 g. It is an open, separable bearing with a pressed-steel cage.
How does the 24780 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 24700-series code marks the dimensional series. The metric dimensions 41.275×76.2×22.225 mm are the converted equivalents of the original inch boundary dimensions.
What do the cone and cup numbers in 24780 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 (24700-series) groups sizes that share the same boundary-dimension plan.
Can a single 24780 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.
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.