This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX135S, 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 SI50BX135S
The AirTAC Airtac SI50 Standard Cylinder SI50BX135S 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 SAI50BX135S, 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 → SAI50BX135S
- 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 SI50BX135S
The AirTAC SI50BX135S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 135mm stroke, and a SUS304 stainless piston rod. It delivers 982N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI50BX135S, which shares identical ISO 15552 mounting dimensions, stroke, and output force.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The original -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI50 Standard Cylinder SI50BX135S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX135S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX135S |
| 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 SAI50BX135S 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 SAI50BX135S 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 SI50BX135S
| 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 SI50BX135S Is Used
Stainless Rod Diverter
Ideal for pushing packages on a washdown conveyor line using the corrosion-resistant SUS304 rod and 982N push force.
Mid-Stroke Clamp
Secures a workpiece at a specific 135mm extension point where standard 125mm or 150mm strokes would fail.
Replacing the Airtac SI50 Standard Cylinder SI50BX135S with the SAI50BX135S
To replace the SI50BX135S, order the SAI50BX135S. Confirm the ISO 15552 mounting interface, the 135mm stroke, G1/4 port, and the SUS304 rod option. Because 135mm is a non-standard stroke, verify your exact spacing. Sizing both ways: a 40mm bore yields 628N push at 0.5MPa, while a 63mm bore yields 1559N. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external pilot check valve or the SAIL/BSAI lock variants. For 135mm strokes, ensure guide alignment to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX135S
- ✓ 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 SI50BX135S FAQ
Yes, the SI50BX135S is discontinued. The direct replacement is the SAI50BX135S. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 135mm stroke, G1/4 port, and mounting interface.
It uses a G1/4 port. The force ratings are: 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, and a theoretical max of 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX135S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX135S replacement — usually within 7-8 hours.