This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX135, 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 SI50BX135
The AirTAC Airtac SI50 Standard Cylinder SI50BX135 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 SAI50BX135, 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 → SAI50BX135
- 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 SI50BX135
The AirTAC SI50BX135 is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 135mm stroke. It delivers 982N push and 825N pull at 0.5MPa through a G1/4 port. The direct replacement is the SAI50BX135, matching the interface, force, and mounting. This specific SKU features a SUS304 stainless steel rod (corrosion-resistant) but lacks a magnet, meaning it cannot accept position sensors.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. Note that air cushions only decelerate the piston; they do not hold loads on air loss, so consider the SAIL lock variant or external pilot check valves for holding requirements.
Airtac SI50 Standard Cylinder SI50BX135 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX135 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX135 |
| 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 SAI50BX135 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 SAI50BX135 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 SI50BX135
| 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 SI50BX135 Is Used
Stainless Rod Clamping
Ideal for packaging machinery requiring corrosion resistance, using the SUS304 rod to clamp components with a safe 589N working load.
Transfer Diverters
Provides reliable 135mm actuation to push products between conveyor lanes, utilizing the 982N thrust at 0.5MPa.
Vertical Lift Gates
Suitable for raising lightweight access gates up to 50kg, provided external pilot check valves secure the load.
Replacing the Airtac SI50 Standard Cylinder SI50BX135 with the SAI50BX135
To replace the SI50BX135, order the SAI50BX135, confirming the ISO 15552 mounting interface, 135mm stroke, and G1/4 porting. Because this SKU has no -S magnet, it cannot support legacy CS1-B/DS1-B switches; if sensing is needed, specify a magnet on the new SAI order. Sizing both ways: stepping down to a 40mm bore yields 628N push @0.5MPa, while stepping up to 63mm provides 1559N. The 50mm bore itself offers 1374N @0.7MPa and a 200kgf maximum @1.0MPa. For load holding without live air, a plain cylinder drifts; use an external rod lock, a pilot check valve, or the SAI family's SAIL or BSAI clamp-lock variants. Since the 135mm stroke is under 300mm, severe rod-bending side loads are less critical than on long strokes, but proper guide alignment remains essential.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX135
- ✓ 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 SI50BX135 FAQ
Yes, the SI50BX135 is discontinued. The direct replacement is the AirTAC SAI50BX135. It is dimensionally interchangeable per ISO 15552, maintaining the same 50mm bore, 135mm stroke, G1/4 port, and mounting interface.
The 50mm bore features a G1/4 port and M16x1.5 rod thread. It delivers 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N at 0.9MPa, and a theoretical maximum force of 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX135
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX135 replacement — usually within 7-8 hours.