The 11.2×6.3 mm high-pressure lubrication tube is a three-layer main supply line for centralized lubrication systems, running from pump outlet to manifold at 25 – 40 MPa working pressure. This page covers the size convention, construction, pressure figures, bending and temperature limits, media, and installation. For light-load branch lines, see the 6×1.5 mm tube page; for this pressure class in coiled moving connections, see the helical coil nylon pipe page.
What 11.2×6.3 Means
Read the size as outer diameter x inner diameter: 11.2 – 11.3 mm outside, 6.3 mm bore. The second figure is a bore, not a wall; the 6×1.5 mm tube lists wall thickness instead, so check the convention before comparing sizes.
| Dimension | Specification |
|---|---|
| Outer diameter | 11.2 – 11.3 mm, tolerance 0.1 mm |
| Inner diameter (bore) | 6.3 mm, tolerance 0.05 mm |
| Wall thickness | 2.45 mm, tolerance 0.09 mm |
| Weight | about 78 g/m |
Three-Layer Construction
The inner layer is PA6 or PA12 with a smooth bore for low flow resistance. A precision-wound polyester fiber reinforcement layer spreads pressure load around the circumference and limits expansion under pressure. The outer cover is TPU or nylon, selected for wear and weather resistance.
Burst Rating and Working Pressure
The burst rating is 80 MPa (800 bar), the pressure at which the tube fails in a controlled burst evaluation. That figure is not an operating pressure. For continuous duty, size the circuit inside the 25 – 40 MPa working envelope, and treat the tube as an 80 MPa burst rating against a 25 – 40 MPa working ceiling.
Bending and Temperature Limits
The minimum bend radius is 45 mm static and 50 mm dynamic, both at 20°C. Dynamic routing takes the larger figure because motion adds flexing at the bend. The temperature range is -40°C to +80°C; below -40°C the materials stiffen, and above +80°C they age faster.
Installation and Fittings
Use compression fittings, couplings, or threaded adapters rated 80 MPa or above; a lower-rated fitting caps the line. Add support every 1 – 2 m on horizontal runs so the tube does not sag and chafe. Before commissioning, pressurize the circuit to 1.5 times working pressure and check joints for seepage.
Where This Tube Fits
This size serves main supply runs: pump outlet to manifold, high-pressure grease distribution, and remote lubrication points. It carries mineral lubricating oil, synthetic PAO or ester oil, lithium or calcium greases NLGI 0 – 3, and HLP hydraulic oil. Light-load branch lines after a metering unit belong to the 6×1.5 mm tube. Moving connections needing this pressure class in coil form belong to the helical coil nylon pipe. General low-pressure selection is covered on the 6 mm nylon pipe page.
Honest Limits
- 80 MPa is a burst rating, not a working pressure; continuous duty above 40 MPa needs a different line.
- Water-based and biodegradable media are short-term only, water-based service at 0 – 40°C.
- Bends below 45 mm static or 50 mm dynamic kink the bore.
- A fitting rated below 80 MPa sets the ceiling for the entire run.
If your duty point sits outside these limits, ask for a quote with your pressure and routing details.
What Is Supplied
The scope is the tube itself in the listed dimensions. Name the inner material and cover when ordering. Fittings, couplings, and adapters are quoted separately unless included in your request.
Frequently Asked Questions
Main run or branch line: which tube do I need?
Main runs from pump to manifold at 25 – 40 MPa are this tube. Light-load branches are the 6×1.5 mm tube; coiled moving connections are the helical coil nylon pipe page.
What does 11.2×6.3 mean?
Outer diameter x inner diameter: 11.2 – 11.3 mm outside, 6.3 mm bore. The 6×1.5 mm tube lists wall thickness instead.
What does the 80 MPa burst rating mean?
The pressure at which the tube fails in a controlled burst evaluation. It is a reference figure, not an operating pressure.
What working pressure does it hold?
25 – 40 MPa continuous. Keep relief settings and component ratings inside this band.
Why are the static and dynamic bend radii different?
A static line is bent once, so 45 mm is enough. A dynamic line flexes in service, so 50 mm is the floor.
Which fittings should I use?
Compression fittings, couplings, or threaded adapters rated 80 MPa or above; the fitting rating sets the ceiling for the run. Confirm thread form when ordering.
What temperature range does it cover?
-40°C to +80°C. Outside that band the materials stiffen or age faster.
Which media can it carry?
Mineral lubricating oil, synthetic PAO or ester oil, lithium or calcium greases NLGI 0 – 3, and HLP hydraulic oil. Biodegradable fluids and water-based media are short-term only.
How do I know when to replace the tube?
Replace on signals: cover abrasion exposing the reinforcement, cracks, kinks, or seepage at fittings that returns after retightening.
Who supplies this tube?
IsoHiTech Lubrication Systems is a lubrication equipment supplier founded in 2023, engineering since 2006. For sizing or fitting advice, write to inquiry@isohitech.com or request a quotation through our contact page.
