OK guys - tyres!
Mar 13th 2009 | 10:24 am
#31
Born again atheist
Joined: Jul 2005
Posts: 30,259
From: Europe (to be specified).
Re: OK guys - tyres!
quite.
i found this...
http://www.millertire.ca/Services/Nitrogen.php
6% claimed again. Like you I tend to think 5.99 out of the 6% quoted is simply down to having the right pressure, harder compounds, running strip, alignment and so on.
it is interesting what the web page says about reducing hub corrosion. maybe thats where boeing are coming from too...?
as for N2 being a larger molecule than O2 - the difference is very small, about 3%. the imperfection in the tire would have to be exactly the right size to differentiate between O2 and N2. Besides regular air is only 18% anyway so its not like the tyre is going to go flat.
lies, damn lies and statistics!
a stroke of genius though, charging 20$ to sell people N2. Which is basically a byproduct of O2 production for other applications such as medical and engineering.
i found this...
http://www.millertire.ca/Services/Nitrogen.php
6% claimed again. Like you I tend to think 5.99 out of the 6% quoted is simply down to having the right pressure, harder compounds, running strip, alignment and so on.
it is interesting what the web page says about reducing hub corrosion. maybe thats where boeing are coming from too...?
as for N2 being a larger molecule than O2 - the difference is very small, about 3%. the imperfection in the tire would have to be exactly the right size to differentiate between O2 and N2. Besides regular air is only 18% anyway so its not like the tyre is going to go flat.
lies, damn lies and statistics!
a stroke of genius though, charging 20$ to sell people N2. Which is basically a byproduct of O2 production for other applications such as medical and engineering.
It's actually the molecular weight which matters and oxygen is the heavier and so diffuses more slowly than nitrogen. In terms of maintaining inflation pressure, you're better off with air (marginally).
Mar 13th 2009 | 2:24 pm
#32
Truro NS
Joined: Feb 2006
Posts: 553
Re: OK guys - tyres!
While Im here I did read on another forum from an ex RAF engineer that N2 is preferred to air for aircraft tires mostly because the N2 is dry. Apparently even trace amounts of water can ruin things like seals due to the freeze/thaw cycles involved in flying.
Mar 13th 2009 | 4:14 pm
#33
talking Ter Sami
Joined: Apr 2003
Posts: 1,107
From: hybrid territory
Re: OK guys - tyres!
It's all about correct inflation.
The claim seems to be based on small difference in the molecular sizes of oxygen and nitrogen and the relative rates of diffusion through the rubber. This effect is going to be very small (see http://blogs.consumerreports.org/car...nitrogen-.html for example). If you have any small leaks, diffusion rates through the rubber will not be the main reason for pressure loss.
Checking your air filled tires regularly is probably just as effective.
Are chemists the cool kids who know how to party on a Friday night or what.
http://pubs.acs.org/doi/abs/10.1021/ac60125a014
http://cat.inist.fr/?aModele=afficheN&cpsidt=19034767
http://www.springerlink.com/content/n5788l771uq12x62/
The claim seems to be based on small difference in the molecular sizes of oxygen and nitrogen and the relative rates of diffusion through the rubber. This effect is going to be very small (see http://blogs.consumerreports.org/car...nitrogen-.html for example). If you have any small leaks, diffusion rates through the rubber will not be the main reason for pressure loss.
Checking your air filled tires regularly is probably just as effective.
Are chemists the cool kids who know how to party on a Friday night or what.
http://pubs.acs.org/doi/abs/10.1021/ac60125a014
http://cat.inist.fr/?aModele=afficheN&cpsidt=19034767
http://www.springerlink.com/content/n5788l771uq12x62/
Mar 14th 2009 | 5:18 am
#34
Born again atheist
Joined: Jul 2005
Posts: 30,259
From: Europe (to be specified).
