This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX135S, 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 SI50AX135S
The AirTAC Airtac SI50 Standard Cylinder SI50AX135S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 135mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX135S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke135 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX135S
- 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 SI50AX135S
The AirTAC SI50AX135S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 135mm stroke, and an SUS420J2 stainless steel rod. It delivers 982 N push force at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50AX135S, a direct sharing the exact ISO 15552 mounting interface, bore, stroke, force, and port. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life.
This specific SKU includes a piston magnet for legacy CS1-B/DS1-B sensors and a 135mm stroke (a non-standard length, so confirm stock). The SAI family also introduces variants the SI line lacked, such as the SAIL air-released lock, SAIF built-in valve, and BSAI clamp-lock. Note that a plain cylinder drifts on air loss; the adjustable cushion only decelerates near stroke end. For secure load holding, use an external rod lock or pilot check valve.
Airtac SI50 Standard Cylinder SI50AX135S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX135S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX135S |
| Bore size | Ø50 mm |
| Stroke | 135 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 SAI50AX135S 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 SAI50AX135S 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 SI50AX135S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×135 | 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 SI50AX135S Is Used
Transfer Diverters
Actuates routing gates on conveyor lines, providing reliable 50 kg vertical lift force and smooth deceleration via adjustable air cushions.
Light Material Handling
Pushes or lifts totes in automated storage systems, utilizing the G1/4 port and ISO 15552 mounting for straightforward fixture integration.
Replacing the Airtac SI50 Standard Cylinder SI50AX135S with the SAI50AX135S
To replace the SI50AX135S, order the SAI50AX135S. Confirm the ISO 15552 mounting interface, the 50mm bore, the 135mm stroke, the G1/4 port, and your mounting accessory (LB, FA, TC, etc.). The -S denotes a piston magnet, so specify it to retain switch compatibility. Sizing both ways: a 40mm bore yields 628 N push at 0.5 MPa, while a 63mm bore yields 1559 N. If you need load holding on air loss, step up to the SAIL or BSAI lock variant, or add an external pilot check valve. Because the 135mm stroke is non-standard, verify availability. For any stroke over 300mm, guide the load to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX135S
- ✓ 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 SI50AX135S FAQ
Yes, the SI50AX135S is discontinued. The direct replacement is the SAI50AX135S. It shares the identical ISO 15552 mounting interface, 50mm bore, 135mm stroke, force, and G1/4 port, fitting existing fixtures perfectly.
It features a G1/4 air port. Force ratings are 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N at 0.9 MPa, and a theoretical max of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX135S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX135S replacement — usually within 7-8 hours.