This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X858S, 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 SI40X858S
The AirTAC Airtac SI40 Standard Cylinder SI40X858S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 858mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X858S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke858 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X858S
- 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 SI40X858S
The AirTAC SI40X858S is a discontinued double-acting ISO 15552 profile cylinder featuring a 40 mm bore, 858 mm stroke, and a G1/4 air port. Delivering 628 N push force at 0.5 MPa, it is replaced by the SAI40X858S. This direct successor shares the exact ISO 15552 mounting interface, bore, stroke, and output force, fitting existing fixtures perfectly.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. The SAI family also adds SAIL, SAIF, and BSAI lock variants the SI lacked. Your -S suffix means a piston magnet for CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40X858S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X858S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X858S |
| Bore size | Ø40 mm |
| Stroke | 858 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 SAI40X858S 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 SAI40X858S 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 SI40X858S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×858 | 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 SI40X858S Is Used
Long-Stroke Diversion
Pushes packages across a transfer line with its 858 mm reach, utilizing the 628 N push force at 0.5 MPa to overcome guide friction.
Vertical Material Lift
Raises lightweight totes up to 32 kg in a storage rack, relying on the double-acting profile barrel for smooth vertical actuation.
Component Ejection
Extracts machined parts from a fixture, where the adjustable 27 mm air cushions decelerate the rod safely at stroke end.
Replacing the Airtac SI40 Standard Cylinder SI40X858S with the SAI40X858S
To replace this SI unit, order the SAI40X858S. Verify your ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/4 port, and the M12x1.25 rod thread. Because the 858 mm stroke exceeds 300 mm, use an external guide to prevent rod bending and side-load wear. If you need to upsize, a 50 mm bore gives 982 N push at 0.5 MPa; downsizing to 32 mm yields 402 N. Note that this cylinder drifts without live air; for load holding, use the SAIL lock variant or an external pilot check valve. The -S magnet supports legacy CS1-B/DS1-B sensors.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X858S
- ✓ 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 SI40X858S FAQ
Yes, the SI40X858S is discontinued. The direct replacement is the AirTAC SAI40X858S. It shares the same ISO 15552 mounting interface, 40 mm bore, 858 mm stroke, output force, and G1/4 port, so it drops directly into existing fixtures.
It features a G1/4 air port. The force ratings 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 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 SAI40X858S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X858S replacement — usually within 7-8 hours.