This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX85, 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 SI40BX85
The AirTAC Airtac SI40 Standard Cylinder SI40BX85 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 85mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX85, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke85 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX85
- 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 SI40BX85
The AirTAC SI40BX85 is a discontinued double-acting ISO 15552 profile cylinder featuring a 40mm bore, 85mm stroke, and a SUS304 stainless steel piston rod. Delivering 628 N push force at 0.5 MPa, it is replaced by the SAI40BX85. This direct successor matches the G1/4 port, M12x1.25 thread, and ISO 15552 mounting interface.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. This non-magnet SKU cannot accept a sensor, and the SAI family adds SAIL lock and BSAI clamp-lock variants the SI lacked.
Airtac SI40 Standard Cylinder SI40BX85 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX85 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX85 |
| Bore size | Ø40 mm |
| Stroke | 85 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 SAI40BX85 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 SAI40BX85 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 SI40BX85
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×85 | 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 SI40BX85 Is Used
Stainless Rod Clamping
Ideal for repetitive part clamping in machining cells where the SUS304 rod resists coolant corrosion and the 628 N force secures components firmly.
Transfer Line Diverters
Provides reliable 85mm stroke actuation for diverting lightweight packages on automated transfer lines without exceeding safe load limits.
Vertical Lift Stops
Suitable for raising lightweight product stops or gates up to 32 kg, utilizing the double-acting profile design for smooth vertical motion.
Replacing the Airtac SI40 Standard Cylinder SI40BX85 with the SAI40BX85
To replace this SI40BX85 with the SAI40BX85, verify the ISO 15552 mounting interface, 85mm stroke, and G1/4 port. Because this SKU lacks a magnet (-S), it cannot accept CS1-B/DS1-B switches; order a magnet-equipped version if sensing is needed. The SUS304 (-B) rod is standard here, but carbon steel is available for non-corrosive environments. Sizing both ways: the 40mm bore yields 628 N push at 0.5 MPa (879 N at 0.7 MPa), while a 32mm bore offers 402 N. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX85
- ✓ 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 SI40BX85 FAQ
Yes, the SI40BX85 is discontinued. The direct replacement is the SAI40BX85. It shares the exact same ISO 15552 mounting interface, 40mm bore, 85mm stroke, G1/4 port, and SUS304 rod, fitting existing fixtures perfectly.
The bore is 40mm with a G1/4 air port. 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. The speed range is 30-800 mm/s.
Request a Quote for the SAI40BX85
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX85 replacement — usually within 7-8 hours.