25877-25821 bearing: complete specifications & equivalents

Specification table

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.

Cross references & equivalents

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 25877-25821 model number is decoded

Dimensional interchange map: within the 25800 series at 34.925 mm bore, the 73.025 mm OD and 23.812 mm width are fixed by the ISO 355 plan, so any same-code bearing from another brand shares the mounting envelope; the 19.1 mm section height distinguishes this family from a 302 or 322 of the same bore, and the 480 g mass is the minimum—sealed or snap-ring executions add rotating weight above that catalogue baseline. Why the cup reference matters here: in the 25800-series tables the 25877 cone appears against several cup options. 25877 is the pairing with 25821, and that choice — not the cone — fixes the 73.025 mm OD, the raceway track position and the 23.812 mm assembled width.The SKF 25877/25821 is a 34.925×73.025×23.812 mm single-row tapered roller bearing — an inch-series entry with an asymmetric raceway cut for thrust capacity and separable mounting.In SKF inch-series tables 25877 sits at 34.925 mm bore (1.375 in) with a 73.025 mm cup OD and 23.812 mm total width — dimensions that trace back to the original Timken boundary plan for the 25800-series family. The SKF catalogue adds the ISO 355 dimension-series code after the bare number (e.g. ); it is the dimensional series, not a separate part number. Selection arithmetic: the C0/C ratio is about 0.99 (static 88 kN against dynamic 89.1 kN), typical of a tapered roller sized for axial capacity, and the 9.8 kN fatigue load limit Pu is the equivalent-load floor used in the life calculation. Mounting practice for 25877: the rotating cone takes the interference fit (k5 on a 34.925 mm shaft), the cup slides for axial location, and reversing-thrust duty demands a paired O/X set rather than one bearing.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• On this 34.925 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 25877 pair heats, loses setting control and smears the roller-rib contact.
• The 25800-series inch series at 34.925 mm bore (73.025×23.812 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 25877 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 25877 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
• The 25877 shares its ISO 355 envelope with other tapered bearings of the same code but is not a drop-in replacement for a ball bearing: it cannot run effectively under pure radial load without a minimum axial load, and a deep-groove bearing cannot replace its combined-load duty.
• The 89.1/88 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 25877 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 25877/25821 designation when purchasing and match the execution to the mounting arrangement.