This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX850S, 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 SI125AX850S
The AirTAC SI125 Standard Cylinder SI125AX850S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 850mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX850S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke850 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX850S
- 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 SI125AX850S
The AirTAC SI125AX850S is a discontinued double-acting ISO 15552 profile cylinder with an extruded aluminum barrel and an SUS420J2 stainless piston rod. It delivers 6136 N push force at 0.5 MPa through its G1/2 port. AirTAC replaced this legacy unit with the SAI125AX850S, a direct sharing the exact 125 mm bore, 850 mm stroke, M27x2 thread, and ISO 15552 mounting interface.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also introduces SAIL and BSAI lock variants absent in the SI line. Your -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125AX850S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX850S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX850S |
| Bore size | Ø125 mm |
| Stroke | 850 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 SAI125AX850S 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 SAI125AX850S 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 SI125AX850S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×850 | 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 SI125AX850S Is Used
Heavy Stamping Press
Drives large dies and platens requiring 6136 N push at 0.5 MPa, utilizing the adjustable 40 mm cushion to absorb high kinetic energy.
Bulk Material Divert
Actuates heavy-duty routing gates over an 850 mm travel span, needing external guide rails to prevent side-load damage on the long rod.
Replacing the Airtac SI125 Standard Cylinder SI125AX850S with the SAI125AX850S
To replace the SI125AX850S, order the SAI125AX850S, confirming the ISO 15552 mounting interface, 850 mm stroke, G1/2 port, and SUS420J2 stainless rod. The 850 mm stroke demands external guide support to prevent rod bending and side-load wear. If sizing down, a 100 mm bore yields 3927 N push at 0.5 MPa; sizing up to 160 mm provides 10053 N. A plain cylinder drifts on air loss—the cushion only decelerates—so use a pilot check valve or the SAIL/BSAI lock variant for load holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX850S
- ✓ 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 SI125AX850S FAQ
Yes, the SI125AX850S is discontinued. The direct replacement is the SAI125AX850S. It shares the identical ISO 15552 mounting interface, 125 mm bore, 850 mm stroke, output force, G1/2 port, and SUS420J2 rod material, fitting existing fixtures perfectly.
It features a G1/2 air port. The force ratings are 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N push at 0.9 MPa, and a theoretical maximum of 1251 kgf at 1.0 MPa. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX850S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX850S replacement — usually within 7-8 hours.