This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X1250, 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 SI40X1250
The AirTAC Airtac SI40 Standard Cylinder SI40X1250 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 SAI40X1250, 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 → SAI40X1250
- 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 SI40X1250
The AirTAC SI40X1250 is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 1250 mm stroke. Because 1250 mm exceeds the 1200 mm standard maximum for this bore, this unit is a non-standard, made-to-order configuration. It delivers 628 N push and 528 N pull at 0.5 MPa, utilizing a G1/4 air port and a 16 mm carbon steel piston rod. As this SKU lacks the -S magnet option, it cannot accept a magnetic position switch.
AirTAC replaced the SI family with the SAI series. The SAI40X1250 is the direct replacement, preserving the ISO 15552 mounting interface, bore, stroke, output force, and port size. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. If your application requires load holding on air loss, explore the SAIL or BSAI lock variants, as standard cushions only decelerate.
Airtac SI40 Standard Cylinder SI40X1250 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X1250 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X1250 |
| 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 SAI40X1250 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 SAI40X1250 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 SI40X1250
| 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 SI40X1250 Is Used
Long-Stroke Transfer
Pushes workpieces between machining stations over a 1250 mm travel distance, utilizing external guides to prevent rod bending on the extended 40 mm bore cylinder.
Automated Sorting Divert
Actuates a diverter arm across a wide physical gap, relying on the adjustable 27 mm air cushions to decelerate the payload smoothly at stroke ends.
Replacing the Airtac SI40 Standard Cylinder SI40X1250 with the SAI40X1250
To replace the discontinued SI40X1250, order the SAI40X1250. Confirm your ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/4 port thread (PT, G, or NPT), and note that this non-standard 1250 mm stroke exceeds the 1200 mm bore limit, requiring a made-to-order unit. Because this SKU lacks the -S suffix, it cannot support legacy CS1-B/DS1-B sensors; order the -S option on the SAI if sensing is needed. Sizing both ways: if you need more force, the 50 mm bore provides 982 N push at 0.5 MPa; if you need less, the 32 mm bore offers 402 N. For a 1250 mm stroke, use external guides to prevent rod bending and side-load damage. A plain cylinder drifts without live air—use an external pilot check valve or the SAIL/BSAI lock variant for load holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X1250
- ✓ 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 SI40X1250 FAQ
Yes, the AirTAC SI40X1250 is discontinued. The direct replacement is the SAI40X1250. It is dimensionally interchangeable per ISO 15552, maintaining the same 40 mm bore, 1250 mm stroke, G1/4 port, and mounting interface. The SAI upgrade simply adds a two Y-shaped one-way piston seal for longer life.
The 40 mm bore features a G1/4 air port and a 16 mm rod. Theoretical forces are: 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 maximum force of 128 kgf at 1.0 MPa. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X1250
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X1250 replacement — usually within 7-8 hours.