This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X655S, 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 SI125X655S
The AirTAC SI125 Standard Cylinder SI125X655S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 655mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X655S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke655 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X655S
- 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 SI125X655S
The AirTAC SI125X655S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 655 mm stroke. It delivers 6136 N push force at 0.5 MPa. AirTAC replaced this legacy unit with the SAI125X655S, a direct upgrade retaining the exact ISO 15552 mounting interface, G1/2 port, and 1251 kgf maximum output. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life.
The -S suffix means this SKU includes a piston magnet for legacy CS1-B/DS1-B sensors. The SAI family also introduces the SAIL air-released lock and BSAI clamp-lock variants absent from the SI line, plus Viton H seals for 0-150 C environments.
Airtac SI125 Standard Cylinder SI125X655S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X655S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X655S |
| Bore size | Ø125 mm |
| Stroke | 655 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 SAI125X655S 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 SAI125X655S 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 SI125X655S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×655 | 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 SI125X655S Is Used
Heavy Press Staging
Ideal for positioning heavy metal blanks at stamping presses, utilizing the 6136 N push force to feed material reliably.
Pallet Lift Gates
Drives large vertical palletizing gates where the 313 kg vertical lift capacity handles substantial conveyor loads.
Mold Shuttle Carriers
Shifts heavy injection molds between stations over the 655 mm travel, requiring external guides to prevent rod bending.
Replacing the Airtac SI125 Standard Cylinder SI125X655S with the SAI125X655S
To replace the SI125X655S, order the SAI125X655S. Confirm the ISO 15552 mounting accessory (LB foot, FA flange, TC trunnion, etc.), the G1/2 port thread (PT, G, or NPT), and the -S magnet for current AirTAC switches. If you need less force, step down to a 100 mm bore (3927 N push at 0.5 MPa); if you need more, a 160 mm bore yields 10053 N. Note that a 655 mm stroke demands external guidance to prevent rod bending and side-load damage. A plain cylinder drifts on air loss—the cushion only decelerates—so use the SAIL lock, BSAI clamp-lock, or an external pilot check valve for load holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X655S
- ✓ 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 SI125X655S FAQ
Yes, the SI125X655S is discontinued. The direct replacement is the SAI125X655S. It is dimensionally interchangeable per ISO 15552, matching the 125 mm bore, 655 mm stroke, G1/2 port, and mounting hardware.
The bore is 125 mm with a G1/2 air port. At 0.5 MPa it provides 6136 N push and 5734 pull force. At 0.7 MPa push is 8590 N, and 11045 N at 0.9 MPa. The theoretical maximum force is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X655S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X655S replacement — usually within 7-8 hours.