How to choose the tube diameter for a roller blind
Tube diameter depends on fabric weight, blind width and how much sag you can accept. A short guide.
The visible part of a roller blind is the fabric. Whether the blind travels evenly, avoids sagging in the middle and runs quietly for years depends on the roller tube. Tube diameter is one of the manufacturer's most important technical decisions.
Sag
On a wide blind a thin tube sags in the middle under its own weight and the fabric's. When that happens the fabric drifts to one side and the edges roll into a cone. As width grows, move to a larger diameter or a thicker wall.
Which tube for which job
- Narrow window and light screen fabric: a small tube is enough.
- Standard residential size and dimout fabric: medium diameter, standard wall.
- Wide opening and blackout fabric: large diameter or thick wall, plus a reinforced head unit.
Matching the head unit
The tube diameter must match the head unit's tube adapter exactly. We supply a matching head unit and bracket for every tube diameter.
Finish and alloy
6063 T5 profiles have an even wall thickness, so the tube turns without vibration. Anodised and powder-coated options are available for the parts visible inside the cassette.
