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Michelin Primacy 4 or Pilot Sport 4


Rich
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1 hour ago, Tony said:

Our Nitrogen is dry and inert. Another point is they say the molecule is much larger so less likely to leak through the tyres inner liner or at the bead line.

Absolutely right, but have you looked at the data? There have been various tests that show how little difference it makes.

For example

"Consumer Reports conducted a study comparing nitrogen versus air loss in tires to determine if this benefit of nitrogen was worth the extra cost. They used 31 pairs of various tire models, filled one tire of each pair to 30 psi with air and the other to the same pressure with nitrogen, then left them outside for a year. At the end of the year, they found that all tires lost pressure. The average pressure loss with air was 3.5 psi; with nitrogen the average loss was 2.2 psi – a difference of 1.3 psi over a year".

And of course, if you check your tyre pressures regularly and top up when necessary, there is no difference at all.

Lets suppose that you have a TPMS and you decide to top up when the pressure has fallen by 1 psi. Based on the Consumer Reports figures, if you have air in your tyres, you'll need to top up roughly once in four months. With nitrogen the equivalent figure is about once in six months. Of course, this assumes that you don't get a leaky valve, or a puncture, or decide to change your tyre pressures to correct for tyre wear, or change your "cold" pressure to correct for seasonal changes in ambient temperature, or use a tyre rotation routine that involves changing tyre pressures on front and rear tyres.

And of course if you are using air, any changes are just a question of sticking on that little inflator that we all carry for emergencies.  There are more places offering nitrogen now but it can still be a pain to find one.

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6 hours ago, Tony said:

I know the Vayron uses nitrogen but this form is corrosive resulting in new wheels for every third set of tyres. To me this doesn't make sense because i would think the nitrogen is time dependant rather than tyre dependant.

That only form of nitrogen I know that could be corrosive would be of the nitrogen oxide family but wouldn't know the benefit of filling tyres with it. Nitrogen itself isn't.

I can't see the small advantage over cost for the tyre centre.  Maybe a good marketing ploy to get more people in? If that's the case then it has worked. Also, bear in mind the difference is only in the 22% of other gases in the air as our atmosphere is 78% nitrogen anyway.

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I think nitrogen will be the norm given time so long as it's slightly better and free. One area i can say is fact is that air loss in the bead area impregnates the alloy with water ingestion thus corroding the alloy permitting that annoying slow air loss over days. If dry nitrogen reduces that then there is a value over air.

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  • 3 weeks later...

Just seen this thread, so apologies for the delayed response.

The chemist in me jut begged for attention:-

"Another point is they say the molecule is much larger so less likely to leak through the tyres inner liner or at the bead line"

 

Nitrogen molecule is 155 pm (picometers); oxygen molecule is 152 pm.

That's pretty much the same size, so there will be no difference detectable in the gas diffusion rate - whether through the bead or the rubber.

What will make the difference is that the pure nitrogen filled tyres should last longer as the oxygen will cause the tyre to perish more quickly from the inside (you can't do anything about the outside!). And, as already noted, the nitrogen is dry, whereas compressed air still has moisture in in.

 

Colin

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  • 3 years later...

Sorry for an old thread bump. I don't care about nitrogen, but I am interested to hear from anyone that has had experience of both PS4 and Primacy 4 tyres (ideally on the same car). I'll be needing a set of tyres soon (for a 2014 A3 saloon) and was going to go with the PS4, but since I'm not a hard driver anymore; I don't attack corners or power out of bends - I generally waft around at normal traffic speeds and occasionally get my foot down in the country lanes when it's clear - I could trade a bit of out-and-out grip (I never find the limit anyway, so I have a big buffer) for a bit a more comfortable, quieter ride, and maybe a little mpg gain if poss. 

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