Nitrogen in Car Tyres

Just thought that I would share this recent positive experience on here.

Back in early February this year I needed new tyres on the front of my car, so as per usual I went along to Micheldever Tyres. They had previously asked if I wanted Nitrogen in them rather than compressed air, I figured that with the volume of Nitrogen in the air we breathe it was all the Emperors new clothes. This time I relented and spent the £3.20.

Fast forward to last week and I needed replacement front tyres, as it turns out the Tyres that were coming off had travelled 28,000 miles and considering the weight of a 2.2l diesel and the torque transmitted through them every day I can't remember getting that sort of distance out of a set of fronts (even Michelins that traditionally go further than most others) . Then add into that driving to Germany with work so the Autobahn had to be taken advantage of with 140mph on the clock and over 200 miles racked up in under 2hrs, a trip down to Spain and back in the summer, both trips with a fully laden car. In all that time and various temperature extremes the tyres were never topped up as the pressure remained at the 33psi put in on a chilly day in February. Added to this the fuel consumption has improved from an average 540 miles a tank to around 600 and over.

The maintaining of tyre pressure impressed me enough to have Nitrogen put in the Wife's tyres simply because she is carp at checking the pressures, and they were always soggy on the rare occasion I took her car out.

One of my clients is ATS Euromaster (Michelin) and when this idea came to market, it was suggested I got Nitrogen put in my tyres.

I would recommend it for longevity of the tyre, fuel consumption, and also for those who rarely check their tyres pressure.

The science behind it has been explained to me, but the general scientific idea is that the nitrogen will escape less than air.

Isn't it something to do with the volume remaining much more constant with changes in temperature (and altitude) meaning more consistent pressures?

Is is something to do with the molecule size on nitrogen and being so large they can.t escape so easily?

They should use hydrogen. Blow outs would be far more impressive...

Is is something to do with the molecule size on nitrogen and being so large they can.t escape so easily?

Kind of. O2 and N2 are both diatomic molecules - two atoms stuck together (hence the 2), looking like a squished figure of eight. Although relatively similar in overall size to O2, N2 molecules are bigger in one dimension (length). I think...

Isn't it something to do with the volume remaining much more constant with changes in temperature (and altitude) meaning more consistent pressures?

Flying on the Dash 8 (I think) out to the Channel Island a few years back you can see the tyres as the plane is under the wings, on the Tyre markings I noticed " Nitrogen fill only". I guess if you have a tyre full of just air descending from Minus 50 to plus 20c quite quickly the tyre pressures would be compromised, so sticking it in car tyres where the temperature extremes are not as varied it makes sense. Quite amazing that Tyre dealers are happy to prolong the life of the product they rely on as a main income by putting Nitrogen in them.

Flying on the Dash 8 (I think) out to the Channel Island a few years back you can see the tyres as the plane is under the wings, on the Tyre markings I noticed " Nitrogen fill only". I guess if you have a tyre full of just air descending from Minus 50 to plus 20c quite quickly the tyre pressures would be compromised, so sticking it in car tyres where the temperature extremes are not as varied it makes sense. Quite amazing that Tyre dealers are happy to prolong the life of the product they rely on as a main income by putting Nitrogen in them.

Nitrogen is used because in overheating/fire situations, caused by, for example a max weight aborted take off at high speed, especially in aircraft 200/300 tons at 200 mph, bursting tyres would flood the fire with oxygen but nitrogen is inert so doesn't. There was talk of fitting aircraft with nitrogen supplies to fill the voids in fuel tanks after fuel is used or the tank empty, (as per the TWA B747 that blew up after takeoff due empty centre tank cooking off) so that combustion wouldn't occur. Bit like cabin sprinkler systems. Weight considerations and cost put that to bed. Airlines always say "Safety is paramount", what they mean is, as long as it doesn't cost money.

Do you top up with Air though as I haven't seen any nitrogen available to top up at garages?

I think the idea is that you shouldn't need to top up..... that's what previous posters are saying

Is is something to do with the molecule size on nitrogen and being so large they can.t escape so easily?

Huhh ? Isnt air 4/5 N2 anyway ?

Sounds like snake-oil sales to me...

http://www.theaa.com/motoring_advice/safety/filling-tyres-with-nitrogen.html

and this from a mechanic (with a more vested interest??)

http://www.popularmechanics.com/cars/how-to/repair-questions/4302788

http://www.theaa.com/motoring_advice/safety/filling-tyres-with-nitrogen.html

Well that's that then.

Well that's that then.

And another

http://www.thetruthaboutcars.com/2007/10/the-truth-about-filling-your-tires-with-nitrogen/

Time for a Mythbusters episode methinks...

Yep, thought it was b*ll*cks...

Does anyone know how big the minute holes in a bit of rubber are? A damn sight bigger than a molecule of Nitrogen I'm willing to bet!