This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX185S, 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 SI50 Standard Cylinder SI50BX185S
The AirTAC Airtac SI50 Standard Cylinder SI50BX185S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 185mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX185S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke185 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX185S
- 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 SI50 Standard Cylinder SI50BX185S
The AirTAC SI50BX185S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 185mm stroke, and a SUS304 stainless steel rod. Delivering 982 N push force at 0.5 MPa, it is replaced by the SAI50BX185S. This direct upgrade keeps the same G1/4 port, M16x1.5 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 built-in magnet supports legacy CS1-B/DS1-B sensors, while Viton H seals can raise the temperature range to 0-150 C.
Airtac SI50 Standard Cylinder SI50BX185S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX185S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX185S |
| Bore size | Ø50 mm |
| Stroke | 185 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| 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, 30 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI50BX185S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 kgf | |
The SAI50BX185S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI50 Standard Cylinder SI50BX185S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×185 | 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 SI50 Standard Cylinder SI50BX185S Is Used
Stainless Rod Diverters
Ideal for washdown conveyor diverters using the SUS304 rod, providing 982 N push force to reliably pivot or block packages on a moving belt.
Packaging Stop Gates
The 185mm stroke actuates stop gates in packaging lines, while the adjustable 30mm air cushions ensure smooth deceleration at cycle end.
Replacing the Airtac SI50 Standard Cylinder SI50BX185S with the SAI50BX185S
To replace the SI50BX185S, order the SAI50BX185S. Verify the ISO 15552 mounting interface, 185mm stroke, G1/4 port, and the -S magnet for CS1-B/DS1-B switches. The -B code specifies the SUS304 stainless rod for corrosion resistance. For sizing, a 40mm bore yields 628 N push at 0.5 MPa, while a 63mm bore yields 1559 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. Since 185mm is under 300mm, side-load risks are minimal, but standard guide considerations apply.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX185S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI50 Standard Cylinder SI50BX185S FAQ
Yes, the SI50BX185S is discontinued. The direct replacement is the SAI50BX185S. It features the same ISO 15552 mounting interface, 50mm bore, 185mm stroke, output force, G1/4 port, and SUS304 stainless rod, fitting existing fixtures perfectly.
The 50mm bore uses a G1/4 air port. At 0.5 MPa it provides 982 N push and 825 N pull force. At 0.7 MPa push is 1374 N, and at 0.9 MPa it is 1767 N. The theoretical maximum force is 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX185S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX185S replacement — usually within 7-8 hours.