This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X135FA, 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 SI50X135FA
The AirTAC Airtac SI50 Standard Cylinder SI50X135FA 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 SAI50X135FA, 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 → SAI50X135FA
- 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 SI50X135FA
The AirTAC SI50X135FA is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore, 135mm stroke, and an FA flange mounting interface. Delivering 982 N push force at 0.5 MPa, it is replaced by the SAI50X135FA. This direct successor matches the exact bore, stroke, output, G1/4 port, and ISO 15552 mounting dimensions for existing fixtures.
The SAI upgrade introduces a refined piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. Note this specific SKU lacks a magnet, so it cannot accept position sensors; the legacy SI family used CS1-B/DS1-B switches on magnetized versions. The SAI family also adds SAIL, SAIF, and BSAI lock variants absent in the SI line.
Airtac SI50 Standard Cylinder SI50X135FA Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X135FA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X135FA |
| 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 SAI50X135FA 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 SAI50X135FA 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 SI50X135FA
| 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 SI50X135FA Is Used
Clamping Fixtures
Secures medium-duty workpieces on machining lines, utilizing the 982 N push force at 0.5 MPa to hold components firmly during secondary operations.
Package Diverting
Drives 135mm stroke diverting arms on packaging conveyors to route boxes, relying on the FA flange mount to maintain rigid alignment under lateral stress.
Replacing the Airtac SI50 Standard Cylinder SI50X135FA with the SAI50X135FA
To replace the SI50X135FA, order the SAI50X135FA. Confirm the ISO 15552 FA flange interface, 50mm bore, 135mm stroke, G1/4 port (PT/G/NPT thread options), and double-acting operation. Because this SKU has no magnet (-S), it cannot support switches; if sensing is needed, order an SAI50X135FAS instead. For sizing, the 50mm bore yields 982 N push at 0.5 MPa; dropping to a 40mm bore reduces push to 628 N, while stepping up to a 63mm bore increases it to 1559 N. Since this is a plain cylinder, it will not hold a load without live air—the cushions only decelerate. For load holding, use an external pilot check valve or explore the SAIL or BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X135FA
- ✓ 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 SI50X135FA FAQ
Yes, the SI50X135FA is discontinued. The direct replacement is the SAI50X135FA. It shares the identical ISO 15552 mounting interface, 50mm bore, 135mm stroke, force, G1/4 port, and FA flange, fitting directly into existing machinery.
The bore is 50mm with a G1/4 air port. At 0.5 MPa it provides 982 N push and 825 N pull force. At 0.7 MPa push is 1374 N, and the theoretical maximum force is 200 kgf at 1.0 MPa. It operates at speeds of 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X135FA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X135FA replacement — usually within 7-8 hours.