This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X173S, 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 SI50X173S
The AirTAC Airtac SI50 Standard Cylinder SI50X173S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 173mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X173S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke173 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X173S
- 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 SI50X173S
The AirTAC SI50X173S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 173mm stroke. Delivering 982 N push force at 0.5 MPa, it is replaced directly by the SAI50X173S. This upgrade keeps the G1/4 port, M16x1.5 rod thread, and 30mm cushions, dropping into existing fixtures seamlessly.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL lock and SAIF valve variants the SI lacked.
Airtac SI50 Standard Cylinder SI50X173S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X173S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X173S |
| Bore size | Ø50 mm |
| Stroke | 173 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 SAI50X173S 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 SAI50X173S 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 SI50X173S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×173 | 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 SI50X173S Is Used
Package Diverting
Actuates routing gates on packaging lines, using the 173mm stroke to shift parcels cleanly between adjacent belt lanes.
Pallet Stops
Raises and lowers physical stop pins at pallet transfer stations, securely holding 50kg Euro pallets before the lift table cycles.
Light Pressing
Provides consistent downward pressure for seating bearings or pins into housings, utilizing the 982 N push force at 0.5 MPa.
Replacing the Airtac SI50 Standard Cylinder SI50X173S with the SAI50X173S
To replace the SI50X173S, order the SAI50X173S and confirm the ISO 15552 mounting interface, 173mm stroke, G1/4 port, and your mounting accessory (LB, FA, TC, etc.). The -S suffix means a piston magnet is present for CS1-B/DS1-B switches; if ordering the SAI, ensure current AirTAC switches are specified. For sizing, a 50mm bore yields 982 N push at 0.5 MPa; if you need less force, step down to a 40mm bore (628 N), or step up to 63mm (1559 N) for heavier loads. Because stroke exceeds 150mm, verify guide alignment to prevent rod bending and side-load wear. Note that a plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant for held loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X173S
- ✓ 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 SI50X173S FAQ
Yes, the SI50X173S is discontinued. The direct replacement is the AirTAC SAI50X173S. It is dimensionally interchangeable per ISO 15552, maintaining the exact same 50mm bore, 173mm stroke, output force, G1/4 port, and mounting interface to fit your existing fixtures.
The 50mm bore features a G1/4 air port and provides 982 N push / 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical maximum force of 200 kgf at 1.0 MPa. It operates at 30-800 mm/s with a 30mm adjustable air cushion at each end.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X173S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X173S replacement — usually within 7-8 hours.