129-TN9 bearing: complete specifications & equivalents
The 129-TN9 is a ISO 15 radial bearing sized 9 x 26 x 8 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 9 mm |
| Outer diameter D | 26 mm |
| Width B | 8 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 3.9 kN |
| Basic static load rating C0 | 0.82 kN |
| Fatigue load limit Pu | 0.043 kN |
| Reference speed (thermal) | 60000 rpm |
| Limiting speed (mechanical) | 38000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 22 g |
| Manufacturer designation | 129 TN9 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); 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 & 1200-series range
| Bore d | 0.354 in |
|---|---|
| Outer diameter D | 1.024 in |
| Width B | 0.315 in |
| ISO bore code | 29 |
| Radial section height (D−d)/2 | 8.5 mm |
| Smallest bore in 1200-series | 6 mm |
| Largest outer diameter in 1200-series | 230 mm |
| Width range across 1200-series | 6–154 mm |
| Bore position in 1200-series (smallest first) | 4 of 32 |
| Bore above smallest 1200-series size | 3 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 129-TN9 model number is decoded
The 12xx series is the light/normal-section self-aligning ball bearing (ISO dimension series 02). the final digit of 129 is the bore in millimetres: 129 TN9 fits a 9 mm shaft (direct miniature spelling). Envelope 9×26×8 mm (0.354×1.024×0.315 in) with a 8.5 mm radial section height, C 3.9 kN, C0 0.82 kN and Pu 0.043 kN. The open 129 TN9 carries no shields or seals and relies on application lubrication and external sealing. The TN9 suffix identifies the glass-fibre-reinforced polyamide 66 cage execution. The bore is cylindrical (straight), for a press-fit on a 9 mm shaft. Reference (thermal) speed 60000 r/min, limiting speed 38000 r/min, catalogue mass 22 g.
Typical equipment & failure modes
Common applications
- small electric motors
- conveyor idler rollers
- agricultural machinery shafts
- textile spindles and looms
Known failure patterns
- lubricant starvation where no regreasing interval is maintained
- contamination wear when the open arrangement is used without adequate external sealing
- false brinelling from vibration while the shaft stands idle
- fretting corrosion on a creeping shaft or housing seat
Selection pitfalls — read before you substitute
- Fillet radii must clear the 129-TN9 chamfer so the 8 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
- Mount 129-TN9 by heating the inner ring (max 120 °C) on a cylindrical bore — driving it home through the outer ring or balls brinells the raceways.
- The TN9 suffix on 129-TN9 denotes a glass-fibre-reinforced polyamide 66 cage: quiet and light at the 38000 r/min limiting speed, but it softens above roughly 120 °C — check the oil temperature in hot drives.
- The spherical outer raceway lets 129-TN9 tolerate shaft deflection, but it does not increase thrust capacity — combined loads still need an angular-contact or deep-groove bearing.
- Fillet radii must clear the 129-TN9 chamfer so the 8 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
- Self-aligning ball bearings tolerate up to roughly 2–3° of static misalignment, but the sealed 129-TN9 (2RS1) allows less — the lip seal binds before the spherical raceway does.
Frequently asked questions
What are the dimensions of 129-TN9?
SKF 129 TN9 measures 9 mm bore × 26 mm OD × 8 mm width (0.354 × 1.024 × 0.315 in), mass about 22 g. It is open, with no shields or seals.
How do I read the 129 designation?
Miniature self-aligning bearings print the bore as the final digit, so 129 is a 9 mm bearing; the leading digits give the section family.
Which fits should I use for 129-TN9?
With a rotating inner ring use roughly j5/k5 on the shaft and H7 in the 26 mm housing; reverse the interference if the outer ring rotates.
How heavy is 129-TN9?
Catalogue mass is 22 g for 129 TN9; seal and cage executions of the same envelope differ by a few grams.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.