A tubeless tyre has nothing other than the tyre and the wheel and they seal together to create an airtight space.
A tubed tyre has a separate inner tube that holds the air and keeps the tyre inflated.
A very good example is a pushbike wheel with spokes, because it has loads of holes in the rim it **needs** an innertube to hold in the air and to keep inflated.
A Car wheel without spokes has NO holes through it so it can create a chamber with the tire to hold the air in.
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