STO-15 bearing: complete specifications & equivalents
The STO-15 is a ISO 15 radial bearing sized 15 x 35 x 12 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 15 mm |
| Outer diameter D | 35 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 9.13 kN |
| Basic static load rating C0 | 10.6 kN |
| Fatigue load limit Pu | 1.27 kN |
| Limiting speed (mechanical) | 5000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 63 g |
| Manufacturer designation | STO 15 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 15 support rollers / ch. 16 cam followers |
| Last verified | 2026-09-30 |
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.
Dimensions in inches & STO-series range
| Bore d | 0.591 in |
|---|---|
| Outer diameter D | 1.378 in |
| Width B | 0.472 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 10 mm |
| Smallest bore in STO-series | 6 mm |
| Largest outer diameter in STO-series | 80 mm |
| Width range across STO-series | 10–20 mm |
| Bore position in STO-series (smallest first) | 5 of 11 |
| Bore above smallest STO-series size | 9 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| STO | 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 STO-15 model number is decoded
the 35 mm outside diameter runs on the track while the 15 mm bore takes the pin or shaft; the 12 mm overall width spreads the Hertzian contact over the outer ring published ratings C 9.13 kN and C0 10.6 kN already include the bending-stress correction for the unsupported outer ring — the C/C0 ratio of 0.86 is typical for support roller without flange rings, with inner ring executions fatigue load limit Pu 1.27 kN at 15 mm bore gives a specific load of 0.61 kN per mm; the limiting speed is 5,000 r/min the 12 mm width carries the load at 0.76 kN per mm of roller complement; section height 10.0 mm between bore and track surface determines the outer-ring bending stiffness mass 63 g over a 35x12 mm envelope works out to 0.150 g per mm² of projected area — a useful figure when sizing the drive inertia for medium-high-speed cam duty the 15 mm bore puts this in the small-to-medium transition where the roller complement is still needle-type but the outer ring is thick enough for moderate shock loads 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 linear guide and track systems, robotic arm track guidance and paper mill web guide rollers this size is commonly specified for linear guide and track systems and robotic arm track guidance, where the 35 mm track diameter and 15 mm bore fit standard cam and rail geometries in paper mill web guide rollers the 35 mm outer ring provides the rolling contact while the inner ring bore simplifies mounting; the 63 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
Common applications
- automotive welding jig positioners
- linear guide and track systems
- conveyor transfer and diverting rollers
- woodworking machinery feed rollers
Known failure patterns
- without flange rings the roller needs lateral guidance from the housing shoulders — running without side support lets the roller walk off the track
- the open design has no integral sealing; in dusty environments contamination enters directly between the needle rollers and the raceway
- 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
- without integral flanges, axial float must be controlled by external washers or circlips — free axial movement causes edge loading on the outer ring
- the needle roller complement is sensitive to misalignment; a bent shaft or angled track creates uneven load distribution and early raceway pitting
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
Frequently asked questions
What are the dimensions of the STO-15?
STO-15 is a support roller without flange rings, with inner ring with 35 mm outside diameter, 15 mm bore diameter and 12 mm overall width. The bore is 15 mm and the track contact diameter is 35 mm.
What does the STO designation mean?
The STO prefix identifies this as a support roller without flange rings, with inner ring. In the SKF catalogue this designation carries the full specification including the 35x15x12 mm envelope and the 5000 r/min limiting speed.
What is the load capacity of STO-15?
The published basic dynamic load rating C is 9.13 kN and the basic static load rating C0 is 10.6 kN. These values already include the bending-stress correction for the thick-walled outer ring running on a track.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 15 support rollers / ch. 16 cam followers on 2026-09-30. Read our editorial & correction policy.