I want to tubeless some flat 50mm B+ rims, tyres are very loose on them so I need to pack the width of the time out.

Any ideas of what to use?

I wondered about closed cell foam packing material, no idea where to buy. Bubble wrap surerly too fragile (tho I am tempted!)

Pipe insulation?

Camping mat if you have a deep well to fill. Dirt cheap from Argos.

I then use electrical (insulation) tape to seal and create a smooth surface.

Ghetto them…
I’ve had folk question why I ghetto’ my Dually’s…
TBH, it was just easier.
Tyre went on, sealant in. No frantic pumping, they went up with hardly any air loss at all.

Way too loose for that taki.

Cheers guys!

I’d try the bubble wrap. It only needs to fill a gap, not resist any particular forces. It’s done its job as soon as the tyre’s seated, so it doesn’t need to be durable. Parcel tape over the top, see what happens.

I probably will, buy it will need to resist 15psi odd of tyre pressure.