This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX55S, with the same bore, stroke, output force, port and mounting, so it fits the same application. The SAI replacement keeps the same ISO 15552 mounting interface, bore, stroke, output force and accessories, so it drops straight into existing fixtures. It is the current-production version of this cylinder with an upgraded piston seal.
Airtac SI125 Standard Cylinder SI125AX55S
The AirTAC SI125 Standard Cylinder SI125AX55S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 55mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX55S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke55 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX55S
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac SI125 Standard Cylinder SI125AX55S
The AirTAC SI125AX55S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 55mm stroke. Delivering 6136N push force at 0.5MPa, it features a SUS420J2 stainless piston rod and a G1/2 port. The direct replacement is the SAI125AX55S, which matches the original bore, stroke, force, port, and ISO 15552 mounting interface exactly.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. This -S model includes a piston magnet for legacy CS1-B/DS1-B sensors, while the SAI replacement uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125AX55S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX55S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX55S |
| Bore size | Ø125 mm |
| Stroke | 55 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2.0 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 500 mm/s |
| Cushion | Adjustable, 40 mm |
| Max standard stroke | Up to 1500 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI125AX55S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
The SAI125AX55S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI125 Standard Cylinder SI125AX55S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×55 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Legacy SI-family variants: SID (double rod), SIJ (adjustable stroke) — each maps to its SAI equivalent (SID→SAID, SIJ→SAIJ). Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B).
Where the Airtac SI125 Standard Cylinder SI125AX55S Is Used
Heavy-Duty Pressing
Applies the 6136N thrust at 0.5MPa for seating large bearings and heavy components in automated assembly lines.
Pallet Positioning
Handles robust 55mm stroke indexing and stops for loaded pallets, utilizing the 32mm rod rigidity.
Material Forming
Performs short-stroke metal bending or plastic forming operations requiring high output force.
Replacing the Airtac SI125 Standard Cylinder SI125AX55S with the SAI125AX55S
To replace the SI125AX55S, order the SAI125AX55S. Confirm the ISO 15552 mounting interface, 125mm bore, 55mm stroke, G1/2 port, and mounting accessory. The -S magnet and -A SUS420J2 rod carry over directly. If you need more force, the 160mm bore offers 10053N at 0.5MPa; if less is acceptable, the 100mm bore provides 3927N. Note that a plain cylinder drifts on air loss—the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. The SAI family also adds the SAIF self-valve option.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX55S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI125 Standard Cylinder SI125AX55S FAQ
Yes, the SI125AX55S is discontinued. The direct replacement is the SAI125AX55S. It is dimensionally interchangeable per ISO 15552, keeping the same 125mm bore, 55mm stroke, force, G1/2 port, and mounting fixtures.
The G1/2 port bore delivers 6136N push and 5734N pull at 0.5MPa, 8590N push at 0.7MPa, 11045N at 0.9MPa, and a 1251kgf maximum at 1.0MPa. Operating speed is 30-500mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX55S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX55S replacement — usually within 7-8 hours.