STO20 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 STO20 model number is decoded

envelope 20×47×15.8 mm: the 47 mm outside diameter is the track-running surface — a thick-walled outer ring over a 20 mm bore — and the 15.8 mm width sets the contact width on the mating track the catalogue lists C 16.1 kN and C0 22 kN for the STO yoke-type track roller with inner ring, without axial guidance; the C/C0 ratio of 0.73 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 3.1 kN at 20 mm bore, equivalent to 0.81 kN of dynamic rating per millimetre — the limiting speed is 2,400 r/min and, as for HR1 track rollers, no thermal reference speed is published the 20 mm bore takes the mounting pin or shaft; across the 15.8 mm contact width the dynamic rating works out to 1.02 kN per millimetre of rolling-element complement mass is 152 g, or 0.20 g per mm² of the 47×15.8 mm track envelope — inertia that the drive must accelerate on every index of the cam at 20 mm pin bore this size balances the 47 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range STO rollers are used on cam tracks and rail guidance where sealing is handled externally; the open form is easy to relubricate through the pin where drilled 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 automotive welding jig rollers, conveyor transfer and diverting stations and automatic assembly machine carriages, where the 47 mm track diameter and 16.1 kN dynamic rating match the duty. In automotive welding jig rollers the unit fits a compact 20 mm seat, and in conveyor transfer and diverting stations the 152 g mass keeps follower kinetics light. Designers also specify it for automatic assembly machine carriages, relying on the 15.8 mm width and the published 22 kN static rating. Sealed PP/2RSR units are greased for life: never add a grease nipple, and respect the lower limiting speed imposed by the rubbing lips. The crowned outer profile tolerates only small skew; a track that departs by more than the catalogue angle still causes edge loading.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Sealed PP/2RSR units are greased for life: never add a grease nipple, and respect the lower limiting speed imposed by the rubbing lips.
• The crowned outer profile tolerates only small skew; a track that departs by more than the catalogue angle still causes edge loading.
• 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.