This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX85, 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 SI50BX85
The AirTAC Airtac SI50 Standard Cylinder SI50BX85 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 85mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX85, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke85 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX85
- 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 SI50BX85
The AirTAC SI50BX85 is a discontinued double-acting ISO 15552 profile cylinder with an 85 mm stroke. It delivers 982 N of push force and 825 N of pull force at 0.5 MPa through a G1/4 port. Because this legacy unit is end-of-life, you should order the direct replacement: the SAI50BX85. It shares the same ISO 15552 mounting interface, 50 mm bore, stroke, output force, and porting, fitting directly into existing fixtures.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. This specific SKU lacks a magnet (-S), meaning it cannot accept a position sensor like the legacy CS1-B/DS1-B switches. The SUS304 stainless rod option (-B) provides extra corrosion resistance over the standard carbon steel.
Airtac SI50 Standard Cylinder SI50BX85 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX85 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX85 |
| Bore size | Ø50 mm |
| Stroke | 85 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 SAI50BX85 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 SAI50BX85 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 SI50BX85
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×85 | 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 SI50BX85 Is Used
Package Diverting
Pushes light-to-medium cartons off a main conveyor line using the 85 mm stroke and 982 N thrust at 0.5 MPa.
Clamp Actuation
Secures mild steel workpieces in a machining fixture, providing reliable hold via 825 N of pull force.
Gate Positioning
Indexes sorting gates in a distribution hub, benefiting from the 30-800 mm/s speed range for rapid cycling.
Replacing the Airtac SI50 Standard Cylinder SI50BX85 with the SAI50BX85
To replace the discontinued SI50BX85, order the SAI50BX85. Verify your ISO 15552 mounting interface (LB, FA, TC, etc.), the 85 mm stroke, and the G1/4 port thread (PT, G, or NPT). Because this specific SKU has no magnet, it cannot support switches; if sensing is required, select an SAI50X85S and use current AirTAC switches. For sizing, the 50 mm bore yields 982 N push at 0.5 MPa; if you need less force, step down to a 40 mm bore (628 N), or step up to a 63 mm bore (1559 N) for heavier loads. Remember that a standard cylinder does not hold load without live air—the cushion only decelerates. For load-holding on air loss, use an external pilot check valve or explore the SAIL or BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX85
- ✓ 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 SI50BX85 FAQ
Yes, the AirTAC SI50BX85 is discontinued. The direct replacement is the SAI50BX85. It is dimensionally interchangeable per ISO 15552, retaining the same 50 mm bore, 85 mm stroke, output force, G1/4 port, and mounting accessories.
This double-acting cylinder features a G1/4 air port and a 20 mm piston rod. It generates 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Request a Quote for the SAI50BX85
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX85 replacement — usually within 7-8 hours.