This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X650STC, 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 SI125X650STC
The AirTAC SI125 Standard Cylinder SI125X650STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 650mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X650STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke650 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X650STC
- 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 SI125X650STC
The AirTAC SI125X650STC is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 650 mm stroke. It delivers 6136 N push force at 0.5 MPa. The direct replacement is the SAI125X650STC, which preserves the exact ISO 15552 mounting interface, G1/2 port, and TC trunnion mount. The SAI upgrade features a refined piston seal with two Y-shaped one-way elements for low start-up pressure and extended life.
The -S code denotes a piston magnet for legacy CS1-B/DS1-B sensors (the SAI uses current AirTAC switches). The SAI family also introduces lock and valve variants the SI lacked, like the SAIL and BSAI clamp-lock.
Airtac SI125 Standard Cylinder SI125X650STC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X650STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X650STC |
| Bore size | Ø125 mm |
| Stroke | 650 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 SAI125X650STC 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 SAI125X650STC 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 SI125X650STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×650 | 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 SI125X650STC Is Used
Heavy Material Lifts
Drives large 313 kg vertical lifting platforms using the 6136 N push force at 0.5 MPa, relying on external guides to manage the 650 mm stroke.
Pallet Diversion
Shifts heavy pallets laterally on packaging lines via the TC trunnion mount, absorbing lateral moments with external support.
Automated Storage
Actuates large automated storage and retrieval doors requiring a 650 mm reach and robust 125 mm bore thrust.
Replacing the Airtac SI125 Standard Cylinder SI125X650STC with the SAI125X650STC
To replace the SI125X650STC, order the SAI125X650STC. Confirm the ISO 15552 TC trunnion interface, 650 mm stroke, G1/2 port, and the -S magnet. If downsizing, neighbor bores (100 mm) yield 3927 N push at 0.5 MPa; if upscaling, the 160 mm bore provides 10053 N. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external pilot check valve or the SAIL/BSAI lock variant. At 650 mm stroke, prevent rod bending by guiding the load externally to avoid side-load damage.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X650STC
- ✓ 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 SI125X650STC FAQ
Yes, the SI125X650STC is discontinued. The direct replacement is the SAI125X650STC. It is dimensionally interchangeable per ISO 15552, maintaining the same 125 mm bore, 650 mm stroke, G1/2 port, and TC mounting interface.
The 125 mm bore features a G1/2 port. Force ratings are: 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N push at 0.9 MPa, and a theoretical max of 1251 kgf at 1.0 MPa. Speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X650STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X650STC replacement — usually within 7-8 hours.