This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX55, 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 SI50BX55
The AirTAC Airtac SI50 Standard Cylinder SI50BX55 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 55mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX55, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke55 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX55
- 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 SI50BX55
The AirTAC SI50BX55 is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 55mm stroke. It delivers 982 N push and 825 N pull at 0.5 MPa. The direct replacement is the SAI50BX55, retaining the exact G1/4 port, M16x1.5 thread, and 30mm cushions. This SKU lacks a magnet, so it cannot accept a position switch.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and longevity. The SAI family also adds SAIL and BSAI lock variants absent in the SI line.
Airtac SI50 Standard Cylinder SI50BX55 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX55 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX55 |
| Bore size | Ø50 mm |
| Stroke | 55 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 SAI50BX55 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 SAI50BX55 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 SI50BX55
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×55 | 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 SI50BX55 Is Used
Clamp Actuation
Provides 982 N of clamping force at 0.5 MPa for securing mid-weight aluminum housings during CNC milling operations.
Package Diverting
Drives a 55mm stroke diverter arm to push medium cartons off a main conveyor belt line at speeds up to 800 mm/s.
Pallet Stops
Acts as a pneumatic stop pin for pallets up to 50 kg on gravity roller conveyors, retracting quickly to release flow.
Replacing the Airtac SI50 Standard Cylinder SI50BX55 with the SAI50BX55
To replace the SI50BX55, order the SAI50BX55 to match the ISO 15552 interface, 50mm bore, 55mm stroke, and G1/4 port. Because this specific SKU has no magnet (-S), it cannot support legacy CS1-B/DS1-B sensors; order a magnet-equipped SAI if sensing is needed. Sizing both ways: a 40mm bore yields 628 N push at 0.5 MPa, while a 63mm bore yields 1559 N. Note that a plain cylinder drifts without live air; for load holding, use an external pilot check valve or the SAIL/BSAI lock variants. The 20mm rod handles the 55mm stroke without bending concerns.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX55
- ✓ 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 SI50BX55 FAQ
Yes, the SI50BX55 is discontinued. The direct replacement is the SAI50BX55. It is dimensionally interchangeable per ISO 15552, keeping the same 50mm bore, 55mm stroke, output force, G1/4 port, and mounting fixtures.
This double-acting cylinder features a G1/4 air port and provides 982 N push and 825 N pull at 0.5 MPa. It delivers 1374 N at 0.7 MPa, 1767 N at 0.9 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Request a Quote for the SAI50BX55
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX55 replacement — usually within 7-8 hours.