This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X850S, 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 SI40 Standard Cylinder SI40X850S
The AirTAC Airtac SI40 Standard Cylinder SI40X850S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 850mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X850S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke850 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X850S
- 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 SI40 Standard Cylinder SI40X850S
The AirTAC SI40X850S is a discontinued double-acting ISO 15552 profile cylinder with an extruded aluminum barrel, adjustable air cushions, and a built-in piston magnet for CS1-B/DS1-B switches. Delivering 628 N push force at 0.5 MPa through a 40 mm bore, it is replaced by the SAI40X850S. This direct upgrade shares the same G1/4 port, M12x1.25 rod thread, and ISO 15552 mounting interface.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also adds SAIL, SAIF, and BSAI lock variants absent from the SI line. Note that Viton H seals raise the operating temperature to 0-150 C.
Airtac SI40 Standard Cylinder SI40X850S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X850S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X850S |
| Bore size | Ø40 mm |
| Stroke | 850 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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 – 800 mm/s |
| Cushion | Adjustable, 27 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI40X850S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
The SAI40X850S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI40 Standard Cylinder SI40X850S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | 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 SI40 Standard Cylinder SI40X850S Is Used
Long-Stroke Diversion
Pushes packages across transfer lines using the 850 mm extension, relying on the 628 N thrust to overcome friction without side-loading the rod.
Actuated Guarding
Cycles large access doors on automated cells where the 40 mm bore provides smooth motion and the adjustable cushions decelerate the long travel.
Replacing the Airtac SI40 Standard Cylinder SI40X850S with the SAI40X850S
To replace the SI40X850S, order the SAI40X850S and confirm the ISO 15552 mounting interface, 40 mm bore, 850 mm stroke, G1/4 port (PT/G/NPT), and your mounting accessory. Because this is an 850 mm stroke, use external guides to prevent rod bending and side-load damage. If you need to downsize, a 32 mm bore yields 402 N push at 0.5 MPa; if you need more force, a 50 mm bore provides 982 N. A plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock or pilot check valve for load holding, or specify the SAIL/BSAI lock variant. The -S magnet works with legacy CS1-B/DS1-B sensors; the SAI uses current AirTAC switches.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X850S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI40 Standard Cylinder SI40X850S FAQ
Yes, the SI40X850S is discontinued. The direct replacement is the AirTAC SAI40X850S. It is dimensionally interchangeable per ISO 15552, retaining the same 40 mm bore, 850 mm stroke, G1/4 port, and mounting fixtures.
It features a G1/4 air port and M12x1.25 rod thread. Force output is 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical maximum of 128 kgf at 1.0 MPa. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X850S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X850S replacement — usually within 7-8 hours.