Originally Posted by
Doug_MPS6
The relevant principle is that the N2 molecule is bigger than the O2 molecule and the improved tyre pressure retention arises by virtue of the fact that the larger N2 molecules don't migrate through the porous rubber so easily. The fact that N2 molecules still migrate means that this sought after advantage plainly only applies to the ~21% of the air in your tyre that isn't N2 (e.g, the O2 component).
In my view, unless it is for specialist purposes, such as aircraft (and both my planes ran normal air in their tyres), and assuming you are normally handy to a service station to routinely check your tyre pressures, as you should, stressing over this tiny advantage is a waste of time and money and merely a selling gimmick to tyre certain dealers exploiting tuners.
And pressure being pressure, and acting universally and equally in all directions against the constraints of the void it occupies, it doesn't matter what gas your tyres are filled with, and assuming equal set pressures and all else being equal, it is only in your head if you think the ride feel or roll resistance is any different to that achieved with straight air.
well said Doug, i agree. Its about certain companies trying to exploit $$
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