38880-38820 bearing: complete specifications & equivalents
The 38880-38820 is a ISO 355 radial bearing sized 263.525 x 325.438 x 28.575 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 263.525 mm |
| Outer diameter D | 325.438 mm |
| Width B | 28.575 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 273 kN |
| Basic static load rating C0 | 550 kN |
| Fatigue load limit Pu | 48 kN |
| Reference speed (thermal) | 1400 rpm |
| Limiting speed (mechanical) | 1700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5300 g |
| Manufacturer designation | SKF 38880/38820 |
| 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 & 38800-series range
| Bore d | 10.375 in |
|---|---|
| Outer diameter D | 12.813 in |
| Width B | 1.125 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 31 mm |
| Smallest bore in 38800-series | 263.525 mm |
| Largest outer diameter in 38800-series | 325.438 mm |
| Width range across 38800-series | 28.575–28.575 mm |
| Bore position in 38800-series (smallest first) | 1 of 1 |
| Bore above smallest 38800-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 38880-38820 | 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 38880-38820 model number is decoded
Why the cup reference matters here: in the 38800-series tables the 38880 cone appears against several cup options. 38880 is the pairing with 38820, and that choice — not the cone — fixes the 325.438 mm OD, the raceway track position and the 28.575 mm assembled width.SKF 38880 (SKF 38880/38820) is the 38800-series tapered roller choice for a 263.525 mm shaft — one row of tapered rollers on an asymmetric raceway inside the 325.438×28.575 mm envelope.The 38800-series series assigns 263.525 mm bore, 325.438 mm OD and 28.575 mm width to 38880; the cone and cup references are not interchangeable with other inch-series pairs even when the bore matches, because the cup profile and rib geometry are series-specific. In SKF suffix language a bare 38880 is the standard execution; B marks a larger contact angle and Q or J2 mark clearance/cage variants, all quoted separately. With C 273 kN and C0 550 kN, the 38880 pair-sizing check is dominated by the axial share: keep the equivalent load P below the rating at the required L10, remembering one bearing alone cannot cover reversing thrust at 1,700 r/min. Specify pairs rather than single units wherever thrust reverses: the tapered contact of 38880 generates an induced axial load under radial force, and an unpaired bearing on a reversing shaft will run slack and fret its seat. Journal and housing interface: the 263.525 mm bore takes a m6 shaft seat (upper deviation ~0.527 mm for this diameter range) and the 325.438 mm outside diameter pairs with an H7 housing bore tolerance band of 325.438.000/325.458 mm; the 28.575 mm width defines the shoulder depth, and the 5300 g cone-plus-cup assembly is the dead load on the shaft during thermal expansion calculations.
Typical equipment & failure modes
Common applications
- large industrial mixer shafts
- offshore winch and drawworks drums
- rolling-mill roll-neck bearings
- wind-turbine main 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
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- At 263.525 mm bore the cone mass is high enough that cocking during mounting damages the cage and rib; guide the ring square, confirm seat contact around the full circumference, and re-check setting after the first thermal cycle of the paired set.
- The 320 series at 263.525 mm bore (325.438×28.575 mm) is the low-friction, higher-speed section; it carries less thrust than a 302 of the same bore, so verify the axial load share before swapping.
- O (back-to-back) pairs are stiffer against moments, X (face-to-face) pairs tolerate misalignment and thermal growth better; choosing the arrangement from the 2D drawing rather than the actual shaft thermal expansion is a common 38880 mounting error.
- Setting is a design value, not an assembly feel: excessive preload in the 38880 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 1,400 r/min reference is a thermal criterion under load, while the 1,700 r/min limiting value is the mechanical ceiling — observe both.
- The 273/550 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 38880 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 38880/38820 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
Is 38880 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 38880?
The SKF 38880/38820 is a single-row tapered roller bearing with 263.525 mm bore, 325.438 mm outer diameter and 28.575 mm width (10.375 × 12.813 × 1.125 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 273 kN, C0 550 kN, fatigue load limit Pu 48 kN, reference speed 1,400 r/min, limiting speed 1,700 r/min, mass about 5300 g. It is an open, separable bearing with a pressed-steel cage.
How does the 38880 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 38800-series code marks the dimensional series. The metric dimensions 263.525×325.438×28.575 mm are the converted equivalents of the original inch boundary dimensions.
What do the cone and cup numbers in 38880 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 (38800-series) groups sizes that share the same boundary-dimension plan.
Can a single 38880 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.