guide
tube or tubeless
Cast (alloy) wheels are normally sealed and run tubeless tyres without a tube. Spoked wheels let air past the spoke holes, so they need an inner tube unless the rim is a sealed tubeless type.
- 01
A tube-type tyre always needs a tube. A tubeless tyre can run with a tube of the right size when the wheel is not tubeless.
- 02
The inner tube is sized to the tyre, so it needs the tyre size.
Source: ETRTO Standards Manual (tyre size, load index and speed symbol designations) – read it