This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX55, 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 SI125AX55
The AirTAC SI125 Standard Cylinder SI125AX55 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 SAI125AX55, 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 → SAI125AX55
- 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 SI125AX55
The AirTAC SI125AX55 is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 55 mm stroke. It delivers 6136 N push and 5734 N pull at 0.5 MPa through a G1/2 port. The direct replacement is the SAI125AX55, which preserves the exact ISO 15552 mounting interface, stroke, output force and accessories. This specific SKU features the -A SUS420J2 stainless piston rod for corrosion resistance, but lacks a magnet, meaning it cannot accept a position switch.
The SAI upgrade introduces a refined piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. For applications needing load holding on air loss, the SAI family adds SAIL and BSAI lock variants the SI lacked.
Airtac SI125 Standard Cylinder SI125AX55 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX55 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX55 |
| 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 SAI125AX55 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 SAI125AX55 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 SI125AX55
| 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 SI125AX55 Is Used
Heavy Press Operations
Ideal for high-force pressing and forming tasks where the 6136 N push at 0.5 MPa is required to seat bearings or assemble heavy components.
Stainless Rod Clamping
The SUS420J2 stainless rod option excels in humid manufacturing environments where corrosion resistance is critical for long-term clamping.
Replacing the Airtac SI125 Standard Cylinder SI125AX55 with the SAI125AX55
To replace this SI125AX55 with the SAI125AX55, verify the ISO 15552 mounting fixture, the 55 mm stroke, the G1/2 port, and the -A SUS420J2 rod material. Because this SKU has no -S magnet, it cannot support legacy CS1-B/DS1-B sensors; order an -S version if sensing is required. Sizing both ways: the neighboring 100 mm bore yields 3927 N push at 0.5 MPa, while stepping up to 160 mm provides 10053 N. Note that a plain cylinder drifts on air loss—the cushion only decelerates near stroke end—so use a SAIL lock variant or external pilot check valve for held loads. The M27x2 rod thread and 40 mm cushion remain unchanged.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX55
- ✓ 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 SI125AX55 FAQ
Yes, the SI125AX55 is discontinued. The direct replacement is the AirTAC SAI125AX55. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 55 mm stroke, G1/2 port, and mounting interface.
This double-acting cylinder uses a G1/2 port and generates 6136 N push and 5734 N pull at 0.5 MPa. At 0.7 MPa push is 8590 N, and 11045 N at 0.9 MPa. The theoretical maximum force is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX55
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX55 replacement — usually within 7-8 hours.