This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX550S, 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 SI50BX550S
The AirTAC Airtac SI50 Standard Cylinder SI50BX550S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 550mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX550S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke550 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX550S
- 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 SI50BX550S
The AirTAC SI50BX550S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore, 550 mm stroke, and a SUS304 stainless steel rod. Delivering 982 N push force at 0.5 MPa, it is replaced by the SAI50BX550S. This direct successor shares the exact ISO 15552 mounting interface, G1/4 port, and 200 kgf max force.
The SAI upgrade features two Y-shaped one-way piston seals for low start-up pressure and long life. The SAI family also adds SAIL, SAIF, and BSAI lock variants the SI lacked. Your -S magnet works with legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50BX550S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX550S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX550S |
| Bore size | Ø50 mm |
| Stroke | 550 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 SAI50BX550S 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 SAI50BX550S 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 SI50BX550S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×550 | 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 SI50BX550S Is Used
Long-Stroke Diversion
Pushes packages across transfer lines with 982 N force, using the 550 mm travel to bridge conveyor gaps.
Pallet Handling
Actuates gating arms on packaging stations, benefiting from the 30-800 mm/s speed range and 30 mm cushions.
Replacing the Airtac SI50 Standard Cylinder SI50BX550S with the SAI50BX550S
To replace the SI50BX550S, order the SAI50BX550S. Verify the ISO 15552 mounting fixture, 50 mm bore, 550 mm stroke, G1/4 port, and M16x1.5 rod thread. The -B rod is SUS304 stainless steel; the -S magnet supports CS1-B/DS1-B switches. Sizing both ways: a 40 mm bore yields 628 N push at 0.5 MPa, while a 63 mm bore yields 1559 N. Air cushions only decelerate; they do not hold loads. For load holding on air loss, use an external pilot check valve or the SAIL/BSAI lock variant. Because 550 mm exceeds 300 mm, use external guides to prevent rod bending and side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX550S
- ✓ 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 SI50BX550S FAQ
Yes, the SI50BX550S is discontinued. The direct replacement is the SAI50BX550S. It is dimensionally interchangeable per ISO 15552, retaining the same 50 mm bore, 550 mm stroke, G1/4 port, and mounting interface.
The 50 mm bore features a G1/4 port. It delivers 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical max of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX550S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX550S replacement — usually within 7-8 hours.