This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX55S, 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 SI50BX55S
The AirTAC Airtac SI50 Standard Cylinder SI50BX55S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 55mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX55S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke55 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX55S
- 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 SI50BX55S
The AirTAC SI50BX55S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 55mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI50BX55S, matching the exact bore, stroke, force, port, and ISO 15552 mounting interface.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The -B rod is SUS304 stainless steel, and the -S magnet works with legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50BX55S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX55S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX55S |
| Bore size | Ø50 mm |
| Stroke | 55 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 SAI50BX55S 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 SAI50BX55S 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 SI50BX55S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×55 | 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 SI50BX55S Is Used
Stainless Rod Clamping
Ideal for mid-force clamping tasks where the SUS304 rod resists moisture and corrosion during repetitive machining cycles.
Gate Positioning
Acts as a compact stopper or gate controller in material handling, using its 982N thrust to hold items securely in place.
Replacing the Airtac SI50 Standard Cylinder SI50BX55S with the SAI50BX55S
To replace this SI50BX55S, order the SAI50BX55S. Confirm the ISO 15552 mounting interface, 50mm bore, 55mm stroke, G1/4 port (PT/G/NPT thread), SUS304 stainless rod, and -S magnet for CS1-B/DS1-B switches. For sizing both ways: a 40mm bore yields 628N push at 0.5MPa, while a 63mm bore yields 1559N. Note that a plain cylinder does not hold load on air loss; the cushion only decelerates. For held loads, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. The SAIF variant adds a built-in 4M valve for bores 32-100.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX55S
- ✓ 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 SI50BX55S FAQ
Yes, the SI50BX55S is discontinued. The direct replacement is the SAI50BX55S. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 55mm stroke, 982N force, G1/4 port, and mounting interface.
The 50mm bore features a G1/4 port. Force output is 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX55S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX55S replacement — usually within 7-8 hours.