This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X1250S, 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 SI40X1250S
The AirTAC Airtac SI40 Standard Cylinder SI40X1250S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 1250mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X1250S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke1250 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X1250S
- 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 SI40X1250S
The AirTAC SI40X1250S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 1250mm stroke. Because 1250mm exceeds the 1200mm standard maximum for this bore, it is a non-standard, made-to-order configuration. It delivers 628N push force at 0.5MPa via a G1/4 port. AirTAC replaced the SI line with the SAI40X1250S, a direct upgrade retaining the exact ISO 15552 mounting interface, stroke, and output force.
The SAI upgrade introduces a refined piston seal using two Y-shaped one-way elements for low start-up pressure and extended life. The SAI family also adds SAIL, SAIF, and BSAI lock variants absent in the legacy SI range. This -S model includes a piston magnet for legacy CS1-B/DS1-B sensors; the SAI replacement utilizes current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X1250S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X1250S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X1250S |
| Bore size | Ø40 mm |
| Stroke | 1250 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 SAI40X1250S 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 SAI40X1250S 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 SI40X1250S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×1250 | 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 SI40X1250S Is Used
Long-Stroke Material Transfer
Pushes workpieces between machinery stations over a 1250mm span where external guides absorb lateral stress.
High-Reach Vertical Lift
Elevates 32kg payloads in storage retrieval systems using 0.5MPa shop air, requiring a pilot check valve for safety.
Extended-Axis Positioning
Actuates tooling carriages along extended linear rails, leveraging the 628N thrust for steady clamping operations.
Replacing the Airtac SI40 Standard Cylinder SI40X1250S with the SAI40X1250S
To replace the discontinued SI40X1250S, order the SAI40X1250S direct equivalent, verifying your ISO 15552 mounting accessory (LB, FA, TC, etc.), G1/4 port thread (PT/G/NPT), and M12x1.25 rod-end connection. Since the 1250mm stroke exceeds the 1200mm standard maximum, expect made-to-order lead times. When sizing, note the 628N push force at 0.5MPa; if you need less stroke, a 32mm bore offers 402N, while a 50mm bore provides 982N. For this 1250mm length, external guides are strongly recommended to prevent rod-bending and side-load damage. A standard SAI does not hold load without live air; the cushion only decelerates. For load-holding, use an external pilot check valve, rod lock, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X1250S
- ✓ 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 SI40X1250S FAQ
Yes, the SI40X1250S is discontinued. The direct replacement is the SAI40X1250S. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 1250mm stroke, G1/4 port, and mounting interface, so it drops directly into existing fixtures.
The bore features a G1/4 port and delivers 628N push / 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical max of 128kgf at 1.0MPa. It operates at 30-800mm/s with a 27mm adjustable air cushion at both ends.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X1250S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X1250S replacement — usually within 7-8 hours.