This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X185S, 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 SI125 Standard Cylinder SI125X185S
The AirTAC SI125 Standard Cylinder SI125X185S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 185mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X185S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke185 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X185S
- 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 SI125 Standard Cylinder SI125X185S
The AirTAC SI125X185S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 185 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. AirTAC replaced this legacy unit with the SAI125X185S, a direct upgrade sharing the exact ISO 15552 mounting interface, bore, stroke, and force.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also introduces SAIL and BSAI lock variants absent in the SI line. This -S SKU includes a piston magnet for CS1-B/DS1-B sensors, though the SAI uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125X185S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X185S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X185S |
| Bore size | Ø125 mm |
| Stroke | 185 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2.0 |
| 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 – 500 mm/s |
| Cushion | Adjustable, 40 mm |
| Max standard stroke | Up to 1500 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI125X185S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
The SAI125X185S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI125 Standard Cylinder SI125X185S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×185 | 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 SI125 Standard Cylinder SI125X185S Is Used
Heavy-Duty Pressing
Applies 8590 N of thrust at 0.7 MPa for seating bearings and assembling large components in automated machinery.
Pallet Handling
Lifts and positions heavy loads with a safe working capacity near 3682 N, ideal for distribution center conveyors.
Clamping Fixtures
Secures large workpieces during machining, relying on the 32 mm rod and M27x2 thread for rigid actuation.
Replacing the Airtac SI125 Standard Cylinder SI125X185S with the SAI125X185S
To replace the SI125X185S, order the SAI125X185S. Verify the ISO 15552 mounting interface, 125 mm bore, 185 mm stroke, G1/2 port (PT/G/NPT thread options), and mounting accessory. The -S suffix means a magnet is present for position sensing. If sizing both ways, neighboring bores are 100 mm (3927 N push @0.5 MPa) and 160 mm (10053 N push @0.5 MPa). Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, specify an external pilot check valve or the SAIL/BSAI lock variant. Rod material options include carbon steel, SUS420J2 (A), or SUS304 (B).
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X185S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI125 Standard Cylinder SI125X185S FAQ
Yes, the SI125X185S is discontinued. The direct replacement is the AirTAC SAI125X185S. It shares the identical ISO 15552 mounting interface, 125 mm bore, 185 mm stroke, output force, and G1/2 port, fitting existing fixtures perfectly.
The 125 mm bore provides 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, and 11045 N push at 0.9 MPa, with a theoretical max of 1251 kgf at 1.0 MPa. It operates at 30-500 mm/s, uses a G1/2 port, and has a 40 mm adjustable cushion at each end.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X185S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X185S replacement — usually within 7-8 hours.