STO-40 bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 15 support rollers / ch. 16 cam followers) · extracted 2026-09-30

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 15 support rollers / ch. 16 cam followers); 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 STO-40 model number is decoded

the 80 mm outside diameter runs on the track while the 40 mm bore takes the pin or shaft; the 20 mm overall width spreads the Hertzian contact over the outer ring published ratings C 23.8 kN and C0 39 kN already include the bending-stress correction for the unsupported outer ring — the C/C0 ratio of 0.61 is typical for support roller without flange rings, with inner ring executions fatigue load limit Pu 4.75 kN at 40 mm bore gives a specific load of 0.59 kN per mm; the limiting speed is 1,900 r/min the 20 mm width carries the load at 1.19 kN per mm of roller complement; section height 20.0 mm between bore and track surface determines the outer-ring bending stiffness mass 530 g over a 80x20 mm envelope works out to 0.331 g per mm² of projected area — a useful figure when sizing the drive inertia for low-speed cam duty with a 40 mm bore this is a medium-size track roller — the envelope is large enough for sealed, greased-for-life executions without sacrificing dynamic capacity the STO designation means the simplest yoke-type track roller — needle rollers between an inner ring and the thick-walled outer ring, with no added features beyond the basic load-carrying function typical applications include material handling lift and lower tracks, sheet-metal forming press feeds and textile machine cam drives this size is commonly specified for material handling lift and lower tracks and sheet-metal forming press feeds, where the 80 mm track diameter and 40 mm bore fit standard cam and rail geometries in textile machine cam drives the 80 mm outer ring provides the rolling contact while the inner ring bore simplifies mounting; the 530 g mass is low enough for rapid indexing cycles mounting on a worn or undersized pin reduces the effective clearance and can preload the roller hot the narrow width concentrates the Hertzian contact stress; verify the track material hardness is sufficient for the calculated contact pressure

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• the needle roller complement is sensitive to misalignment; a bent shaft or angled track creates uneven load distribution and early raceway pitting
• mounting on a worn or undersized pin reduces the effective clearance and can preload the roller hot
• without flange rings the roller needs lateral guidance from the housing shoulders — running without side support lets the roller walk off the track