pensioner wrote:

>  Air has a large proportion of N2 in it as
>shipped.  Now if it was He (helium) you might lighten your load
>
The lightened load from the extra lift would be short lived. The helium
molecules are so small as to pass through the interstices in the rubber
of the tyre, in the same way a childs ballon looses it lift when the
helium leaks through the rubber walls.

John Rodgers
88 GL Driver

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