Helium-gas filled frames and tyres, anyone tried it?

[C36]

Rough calculation just for fun
- volume in a single 28mm (counting 25ID in a pure toroydal tire on a 622mm rim): 1L
- Air dens 1.28g/L inflated at 5.5b = 7g
- He dens 0.1785g/L at 5.5b = 0.89g
- H2 dens 0.09 g/L at 5.5b = 0.49g

So that put around 13g of gain at a cost of relatively quick pressure losses.