This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X135S, 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 SI50X135S
The AirTAC Airtac SI50 Standard Cylinder SI50X135S 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 SAI50X135S, 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 → SAI50X135S
- 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 SI50X135S
The AirTAC SI50X135S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 135mm stroke. Delivering 982N push force at 0.5MPa, it is replaced by the SAI50X135S. This direct upgrade keeps the same G1/4 port, M16x1.5 rod thread and mounting interface.
The SAI replacement adds a two Y-shaped one-way piston seal for low start-up pressure. The -S suffix means a piston magnet for CS1-B/DS1-B sensors; SAI uses current AirTAC switches.
Airtac SI50 Standard Cylinder SI50X135S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X135S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X135S |
| 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 SAI50X135S 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 SAI50X135S 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 SI50X135S
| 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 SI50X135S Is Used
Package Diverting
Pushes cartons off a main conveyor line using 982N thrust at 0.5MPa, with the 135mm stroke clearing side guides.
Clamp Actuation
Holds workpieces in a machining fixture, where the 50mm bore provides reliable force and the G1/4 port maintains steady flow.
Pallet Stopper
Acts as a pneumatic stop for incoming pallets, absorbing impact via the 30mm adjustable air cushions at both ends.
Replacing the Airtac SI50 Standard Cylinder SI50X135S with the SAI50X135S
To replace the SI50X135S, order the SAI50X135S. It drops into existing ISO 15552 fixtures with identical 50mm bore, 135mm stroke, G1/4 port (PT/G/NPT thread options) and mounting accessories. The -S magnet is retained. If you need more force, the neighbouring 63mm bore yields 1559N push at 0.5MPa; if less is acceptable, the 40mm bore gives 628N. Because this is a 135mm stroke, ensure adequate guide support to prevent rod bending under side loads. A plain SAI does not hold load without live air; the cushion only decelerates. For load holding, use the SAIL lock, BSAI clamp-lock variant, or an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X135S
- ✓ 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 SI50X135S FAQ
Yes, the SI50X135S is discontinued. The direct replacement is the SAI50X135S. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 135mm stroke, G1/4 port and mounting interface.
The 50mm bore features a G1/4 port. Force outputs are: 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N push at 0.9MPa, and a theoretical maximum of 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X135S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X135S replacement — usually within 7-8 hours.