I’ve probably missed something fundamental, but is this just a narrow tube inside a conventional tubeless setup?
In other words, could I replicate most of the benefits with a 1-1.5″ tube and a second valve hole?

In other words, could I replicate most of the benefits with a 1-1.5″ tube and a second valve hole?

You’d presumably need something tougher than just a normal inner tube or it would just stretch, overinflate and quickly burst.

Thought about that, sure you couldn’t inflate it to 85psi, but don’t forget that the pressure in the tyre will help control the expansion of the tube.

It’s really the bicycle equivalent of a ‘bead lock’ something that has been around for donkies in the off-road/heavy haulage & Military world.

It is more like having a 200g tyre inside.

Thought about that, sure you couldn’t inflate it to 85psi, but don’t forget that the pressure in the tyre will help control the expansion of the tube.

Not really if it’s an 85psi inner and a 15 psi outer. You’d do better just to fit a tubular tyre as the inner if you wanted to bodge it.