This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X550TC, 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 SI125X550TC
The AirTAC SI125 Standard Cylinder SI125X550TC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 550mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X550TC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke550 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X550TC
- 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 SI125X550TC
The AirTAC SI125X550TC is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 550 mm stroke. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125X550TC, which shares the same TC trunnion mounting, M27x2 rod thread, and output force.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. This SKU lacks the -S magnet, so it cannot take CS1-B/DS1-B sensors. For high heat, Viton H seals raise the limit to 150 C.
Airtac SI125 Standard Cylinder SI125X550TC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X550TC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X550TC |
| Bore size | Ø125 mm |
| Stroke | 550 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 SAI125X550TC 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 SAI125X550TC 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 SI125X550TC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×550 | 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 SI125X550TC Is Used
Heavy Stamping Press
Drives large platens and heavy dies where the 6136 N push force at 0.5 MPa handles substantial forming resistance.
Pallet Lift Station
Lifts loaded pallets vertically; the 550 mm stroke provides ample elevation while external guides manage the side loads.
Automated Clamping Fixture
Secures large fabricated components during machining, utilising the TC trunnion mount for pivotal load alignment.
Replacing the Airtac SI125 Standard Cylinder SI125X550TC with the SAI125X550TC
To replace the SI125X550TC, order the SAI125X550TC. Confirm the ISO 15552 TC trunnion interface, 125 mm bore, 550 mm stroke, G1/2 port (PT/G/NPT thread), and M27x2 rod. Because this SKU has no -S magnet, it cannot accept position sensors. Sizing both ways: a 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. With a 550 mm stroke, use external guides to prevent rod bending and side loads. Speed is 30-500 mm/s.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X550TC
- ✓ 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 SI125X550TC FAQ
Yes, the SI125X550TC is discontinued. The direct replacement is the SAI125X550TC. It is dimensionally interchangeable per ISO 15552, matching the 125 mm bore, 550 mm stroke, G1/2 port, and TC mounting interface.
It features a G1/2 port. Force output is 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. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X550TC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X550TC replacement — usually within 7-8 hours.