STO25 bearing: complete specifications & equivalents

Specification table

Source: catalog reference (HR1 2026-09-25) · extracted 2026-09-30

Parameters extracted from the official FAG Rolling Bearings catalogue (HR1 2026-09-25); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.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 STO25 model number is decoded

envelope 25×52×15.8 mm: the 52 mm outside diameter is the track-running surface — a thick-walled outer ring over a 25 mm bore — and the 15.8 mm width sets the contact width on the mating track the catalogue lists C 16.4 kN and C0 23.5 kN for the STO yoke-type track roller with inner ring, without axial guidance; the C/C0 ratio of 0.70 reflects a rolling-element pack sized for heavy static track loading, and the 13.5 mm radial section gives the outer ring its bending stiffness fatigue load limit Cur is 3.35 kN at 25 mm bore, equivalent to 0.66 kN of dynamic rating per millimetre — the limiting speed is 1,800 r/min and, as for HR1 track rollers, no thermal reference speed is published the 25 mm bore takes the mounting pin or shaft; across the 15.8 mm contact width the dynamic rating works out to 1.04 kN per millimetre of rolling-element complement mass is 177 g, or 0.22 g per mm² of the 52×15.8 mm track envelope — inertia that the drive must accelerate on every index of the cam the 25 mm pin bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Because the inner ring is supplied, the mounting pin only needs standard bearing-seat tolerance and surface — hardening to raceway quality is unnecessary Typical applications include woodworking machine feed tracks, cam drives and indexing tables and packaging machine timing mechanisms, where the 52 mm track diameter and 16.4 kN dynamic rating match the duty. In woodworking machine feed tracks the unit fits a compact 25 mm seat, and in cam drives and indexing tables the 177 g mass keeps follower kinetics light. Designers also specify it for packaging machine timing mechanisms, relying on the 15.8 mm width and the published 23.5 kN static rating. Full-complement NATV/NUTR/PWTR rollers make heat and flat-spot easily — slow continuous rotation is fine, stationary load on a turning track is not. The pin or shaft is part of the bearing system: harden it for RSTO/RNA22 positions, and size its deflection because the roller cannot compensate for a bent pin.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Full-complement NATV/NUTR/PWTR rollers make heat and flat-spot easily — slow continuous rotation is fine, stationary load on a turning track is not.
• The pin or shaft is part of the bearing system: harden it for RSTO/RNA22 positions, and size its deflection because the roller cannot compensate for a bent pin.
• Sealed PP/2RSR units are greased for life: never add a grease nipple, and respect the lower limiting speed imposed by the rubbing lips.