This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X135, 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 SI50X135
The AirTAC Airtac SI50 Standard Cylinder SI50X135 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 SAI50X135, 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 → SAI50X135
- 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 SI50X135
The AirTAC SI50X135 is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 135 mm stroke. It delivers 982 N push and 825 N pull at 0.5 MPa through a G1/4 port. Because this legacy unit is end-of-life, you should order the direct replacement: the SAI50X135. It shares the same interface, force, and mounting.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and long life. Note this specific SKU lacks a magnet, so it cannot accept a CS1-B/DS1-B sensor.
Airtac SI50 Standard Cylinder SI50X135 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X135 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X135 |
| 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 SAI50X135 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 SAI50X135 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 SI50X135
| 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 SI50X135 Is Used
Package Diverting
Actuates routing gates on packaging lines using its 135 mm stroke and 982 N thrust to redirect cartons smoothly.
Clamp Actuation
Drives mid-force clamping mechanisms in CNC fixturing where a 50 mm bore provides reliable 0.5 MPa holding.
Replacing the Airtac SI50 Standard Cylinder SI50X135 with the SAI50X135
To replace the SI50X135, order the SAI50X135. Confirm the ISO 15552 mounting interface (LB, FA, TC, etc.), the 135 mm stroke, and the G1/4 port. Because this unit has no -S magnet, it cannot support position sensing; if you need switches, select an SAI50X135S and use current AirTAC sensors. Sizing down, a 40 mm bore yields 628 N push; sizing up, a 63 mm bore provides 1559 N. If your application requires load holding on air loss, note that standard cylinders drift; use an external pilot check valve or the SAIL/BSAI lock variant. At 135 mm stroke, side-load is minimal, but always ensure rigid guidance to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X135
- ✓ 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 SI50X135 FAQ
Yes, the SI50X135 is discontinued. The direct replacement is the AirTAC SAI50X135. It is dimensionally interchangeable per ISO 15552, retaining the same 50 mm bore, 135 mm stroke, output force, G1/4 port, and mounting accessories.
The 50 mm bore features a G1/4 air port and provides 982 N push / 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa. It operates at speeds of 30-800 mm/s.
Request a Quote for the SAI50X135
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X135 replacement — usually within 7-8 hours.