This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX55S, 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 SI50AX55S
The AirTAC Airtac SI50 Standard Cylinder SI50AX55S 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 SAI50AX55S, 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 → SAI50AX55S
- 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 SI50AX55S
The AirTAC SI50AX55S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore, 55mm stroke, and a SUS420J2 stainless steel rod. Delivering 982 N push force at 0.5 MPa, it includes a piston magnet for CS1-B/DS1-B sensors and a G1/4 air port. The direct replacement is the SAI50AX55S, retaining identical ISO 15552 mounting dimensions, output force, and stroke.
The SAI upgrade introduces a two-piece Y-shaped piston seal for lower start-up pressure and extended life. Note that standard cylinders drift without live air; for load holding, consider the SAIL or BSAI lock variants.
Airtac SI50 Standard Cylinder SI50AX55S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX55S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX55S |
| 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 SAI50AX55S 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 SAI50AX55S 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 SI50AX55S
| 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 SI50AX55S Is Used
Stainless Rod Clamping
Ideal for packaging machinery where the SUS420J2 rod resists moisture while providing 982 N of clamping thrust.
Short-Stroke Diversion
The 55mm stroke offers rapid actuation for diverting light to medium products along material handling lines.
Replacing the Airtac SI50 Standard Cylinder SI50AX55S with the SAI50AX55S
To replace the SI50AX55S, order the SAI50AX55S to guarantee the identical ISO 15552 interface, 50mm bore, 55mm stroke, M16x1.5 rod thread, and G1/4 port. Retain your existing mounting hardware and confirm the -S magnet requirement for current AirTAC switches. If downsizing, a 40mm bore yields 628 N push at 0.5 MPa; if upsizing, a 63mm bore provides 1559 N. Because this is a non-locking double-acting cylinder, it will not hold a load without air pressure—the cushions only decelerate the stroke. For secure holding, specify the SAIL air-released lock or BSAI clamp-lock variant, or use an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX55S
- ✓ 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 SI50AX55S FAQ
Yes, the SI50AX55S is discontinued. The direct replacement is the SAI50AX55S. It is dimensionally interchangeable per ISO 15552, matching the 50mm bore, 55mm stroke, G1/4 port, and mounting fixtures.
This double-acting cylinder has a G1/4 air 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 maximum of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX55S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX55S replacement — usually within 7-8 hours.