Nitrogen Filled Tyres

[Nick Jones]

So they are spouting utter tosh.  Who's going call trading standards?  :(

Nick

[Davemate]

cliffhanger wrote:

And why would that stop it?? I am guessing they are relying on osmosis ;)
Pressure differential? pah, that's nothing compared to the go-fasterness of the blurb.

aren't nitrogen molecules larger than oxygen ones ! 8)
in which case it would stop air bleeding through the tyre walls (on a molecular level)

still not worth an exra quid though !

[Clive]

about the same size. see  http://wiki.answers.com/Q/How_does_the_size_of_a_nitrogen_molecule_compare_to_that_of_oxygen

the advantage of N[sub]2[/sub] over O[sub]2[/sub] is that oxygen is a di-radical, and therefor very aggressive. Don't see that as a problem for inside tyres though as UV light seems to cause most problems in the long term.

[drofgum]

cliftyhanger,
That is the point I try to make whenever anyone tries to sell me on nitrogen inflation of tyres. "It keeps the oxygen from attacking the inside of the tyre" Yes, but the inside isn't the place where the tyre needs protection. I see tyres with weathering to the point of exposed fabric at the bottom of the cracks, but the inside looks as good as new or nearly so. The only advantage I can see in nitrogen inflation is that is is dry and therefore no water vapor is inside the tyre to condense and lower the pressure only to re-vaporise and raise the pressure. As to oxygen diffusing through the tyre; the rate of that must be very low; both of my cars spend extended periods sitting unused in the drive, and the drop in pressure is insignificant.
                                                                           Cheers,
                                                                           Paul

[spunkymonkey]

1317 wrote:

cliftyhanger,
As to oxygen diffusing through the tyre; the rate of that must be very low; both of my cars spend extended periods sitting unused in the drive, and the drop in pressure is insignificant.
                                                                           Cheers,
                                                                           Paul

It can actually be fairly high, which is why a "first" inflation usually loses some pressure quite quickly.  But then you top it up and the % of oxygen in the tyre is drastically reduced so the "problem" goes away.  Not worth paying extra for!

I suspect (but my physics is too rusty to do the sums) that the water "problem" is similarly negligible in real-life terms?

[StagNL]

2047 wrote:

I suspect (but my physics is too rusty to do the sums) that the water "problem" is similarly negligible in real-life terms?

My opinion: Unless you race your car and are very concerned about tyre pressues at race temperature, it is very much negligible.