Tubes in tubeless tyres

[CBUEB1771]

I`ve often wondered why, in F1 for example, they don`t fill the tyres with helium or some other light gas. Reducing outboard weight and unsprung weight, in particular. No doubt there is a good reason.
Jim

Now this is a case where molecule size and leakage really come into play. Looking at the Periodic Table we find we are restricted to helium and hydrogen for reasonably convenient materials that are gaseous at standard pressure and temperature and are lighter than air. Hydrogen has a pretty obvious downside, recalling the Hindenburg. Helium has both small atomic radius and is monatomic. Helium even diffuses out of metal containers so it probably wouldn't stay in a tire for very long.