STO30 bearing: complete specifications & equivalents

The STO30 is a ISO 15 radial bearing sized 30 x 62 x 19.8 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.

Bearing dimension schematic Front view shows outer diameter D and bore d; side section shows width B. D = 62 mm d = 30 B = 19.8 mm side section front view
Principal dimensions: bore d 30 mm, outer diameter D 62 mm, width B 19.8 mm. Schematic, not to scale.

Specification table

ParameterValue
Brand FAG
Bore diameter d 30 mm
Outer diameter D 62 mm
Width B 19.8 mm
Material GCr15
Seal / shield open
Internal clearance CN
Tolerance class P0
Cage steel
Basic dynamic load rating C 23.1 kN
Basic static load rating C0 35.5 kN
Fatigue load limit Pu 4.8 kN
Limiting speed (mechanical) 1300 rpm
Operating temperature -40 to +120 °C
Mass 308 g
Manufacturer designation STO30
Standard ISO 15
Catalog version HR1 2026-09-25
Last verified 2026-09-30

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.

Dimensions in inches & sto-series range

Bore d 1.181 in
Outer diameter D 2.441 in
Width B 0.78 in
ISO bore code —
Radial section height (D−d)/2 16 mm
Smallest bore in sto-series 6 mm
Largest outer diameter in sto-series 90 mm
Width range across sto-series 9.8–19.8 mm
Bore position in sto-series (smallest first) 9 of 13
Bore above smallest sto-series size 24 mm

Cross references & equivalents

Equivalent modelBrandMatch levelNote
STO30 ISO 15 full
Dimensions and internal design equivalent — standard interchange.
ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data.

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 STO30 model number is decoded

envelope 30×62×19.8 mm: the 62 mm outside diameter is the track-running surface — a thick-walled outer ring over a 30 mm bore — and the 19.8 mm width sets the contact width on the mating track the catalogue lists C 23.1 kN and C0 35.5 kN for the STO yoke-type track roller with inner ring, without axial guidance; the C/C0 ratio of 0.65 reflects a rolling-element pack sized for heavy static track loading, and the 16.0 mm radial section gives the outer ring its bending stiffness fatigue load limit Cur is 4.8 kN at 30 mm bore, equivalent to 0.77 kN of dynamic rating per millimetre — the limiting speed is 1,300 r/min and, as for HR1 track rollers, no thermal reference speed is published the 30 mm bore takes the mounting pin or shaft; across the 19.8 mm contact width the dynamic rating works out to 1.17 kN per millimetre of rolling-element complement mass is 308 g, or 0.25 g per mm² of the 62×19.8 mm track envelope — inertia that the drive must accelerate on every index of the cam with a 30 mm pin bore the 19.8 mm width and 23.1 kN C rating suit high-cycle industrial machinery rather than instrument 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 cam drives and indexing tables, printing press sheet-transfer grippers and woodworking machine feed tracks, where the 62 mm track diameter and 23.1 kN dynamic rating match the duty. In cam drives and indexing tables the unit fits a compact 30 mm seat, and in printing press sheet-transfer grippers the 308 g mass keeps follower kinetics light. Designers also specify it for woodworking machine feed tracks, relying on the 19.8 mm width and the published 35.5 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

Common applications

  • automatic assembly machine carriages
  • agricultural and textile cam followers
  • linear rail and profile track guidance
  • glass and ceramic line conveyors

Known failure patterns

  • outer-ring fatigue cracking across the unsupported track zone under excessive static load
  • track-side brinelling when the mating rail is softer than the roller running surface
  • flat spots from standing loads or very short oscillating strokes on full-complement rollers
  • seal lip failure and grease loss after sustained running above the limiting speed (PP/2RSR executions)
  • edge wear from skewed tracks that exceed the crowned-profile correction range
  • pin-seat fretting where a hard journal requirement (RSTO/RNA22) was met with a soft pin
  • roller walk-off in flangeless STO/RSTO executions with uncontrolled lateral float
  • contamination entry through open sides in dusty or wash-down environments
  • cage fracture in caged NATR/STO rollers exposed to heavy shock

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.

Frequently asked questions

What are the dimensions of the STO30?

The STO30 is a STO yoke-type track roller with inner ring, without axial guidance with 62 mm outside diameter, 30 mm bore and 19.8 mm width, envelope 30×62×19.8 mm. Mass is 308 g.

What does the STO30 designation mean in the FAG/INA HR1 catalogue?

STO30 identifies this STO yoke-type track roller with inner ring, without axial guidance in the Schaeffler HR1 rolling bearings catalogue. The envelope is 30×62×19.8 mm and the catalogue ratings are C 23.1 kN, C0 35.5 kN, Cur 4.8 kN.

What is the load capacity of the STO30?

The basic dynamic load rating C is 23.1 kN and the basic static load rating C0 is 35.5 kN; the fatigue load limit Cur is 4.8 kN. For track rollers these values already cover the thick-walled outer ring bending case on an unsupported track.

What is the maximum speed of the STO30?

HR1 lists a limiting speed of 1,300 r/min for track rollers and no thermal reference speed. The crowned thick-walled outer ring and (on stud types) the stud contact make the limiting speed the governing figure.

What must the mating track and pin look like for the STO30?

The track should be flat, harder than the roller contact and clean; the crowned 62 mm outer surface tolerates only small angular error. The inner ring lets the 30 mm pin run at normal machined tolerance; lateral guidance comes from the adjacent structure on flangeless executions.

Reviewed & verified by the MPN Base engineering desk against source catalog HR1 2026-09-25 on 2026-09-30. Read our editorial & correction policy.