Nitrogen in tyres

[ba249k]

When I was a Race Mechanic back in the 90's we always use to use Nitrogen in tyres.
I have just stopped at Kwik fit and had them put it in my Burger.
Because trying to check and add air is such a pain with the small wheels. I thought this would be a more stable option ( less checking).
Cost was quoted at £1.50 per wheel - Job done - the mechanic couldn't be bothered walking into the office so didn't charge.
What a nice Kwik fit fitter!


Q: Is there any advantage to using nitrogen instead of compressed air in tires? Will I notice improved fuel economy or a smoother ride? Will my tires last longer?

A: Sort of. From the top: Air is 78 percent nitrogen, just under 21 percent oxygen, and the rest is water vapor, CO2 and small concentrations of noble gases such as neon and argon. We can ignore the other gases.

There are several compelling reasons to use pure nitrogen in tires.

First is that nitrogen is less likely to migrate through tire rubber than is oxygen, which means that your tire pressures will remain more stable over the long term. Racers figured out pretty quickly that tires filled with nitrogen rather than air also exhibit less pressure change with temperature swings. That means more consistent inflation pressures during a race as the tires heat up. And when you're tweaking a race car's handling with half-psi changes, that's important.

Passenger cars can also benefit from the more stable pressures. But there's more: Humidity (water) is a Bad Thing to have inside a tire. Water, present as a vapor or even as a liquid in a tire, causes more of a pressure change with temperature swings than dry air does. It also promotes corrosion of the steel or aluminum rim.

[VOZZA]

And if it's good enough for airliner tyres it's good enough for me.

[Ferrit]

You do realise that air is mostly nitrogen already (and smaller than oxygen which makes up much of the rest) and its free? This is a money scam that started in the states and now is making itself known here.

http://www.scientificamerican.com/artic ... efficiency" onclick="window.open(this.href);return false;

[Deleted User 796]

You do realise that air is mostly nitrogen already (and smaller than oxygen which makes up much of the rest) and its free? This is a money scam that started in the states and now is making itself known here.

http://www.scientificamerican.com/artic ... efficiency" onclick="window.open(this.href);return false;

He does realise as he stated in his post.

I thought it was an informative and interesting post.

[mottza]

This needs to be in the jokes and funnies section.

[Ferrit]

You do realise that air is mostly nitrogen already (and smaller than oxygen which makes up much of the rest) and its free? This is a money scam that started in the states and now is making itself known here.

http://www.scientificamerican.com/artic ... efficiency" onclick="window.open(this.href);return false;

He does realise as he stated in his post.

I thought it was an informative and interesting post.

If he realised, why did he say oxygen would get out before the nitrogen? That is daft and not supported by any science.

[newscooter]

How do they get the air out of the tyres before inflating them with the nitrogen ? If they don't it will be diluted/contaminated from the off. I think this was dreamed up by the F1 teams but may not be of much relevance in the real world.

[Ferrit]

F1 uses Nitrogen as it is not a fire risk and they need compressed gas to run their tools. The same gas they fill the tyres with is the same gas running all their tools....no fire risk.

Not all aircraft have nitrogen, only those that fly and high altitude or have higher than normal landing speed or impact and again, as the FAA state, it is more to do with preventing fire than to do with performance etc

[Data]

Nitrogen is used in many new car tyres by many manufacturers these days. Nissan currently puts it in there performance cars (GT360z for one), as do many many other manufacturers here in the Uk and 'Urop'. Some heavy commercial vehicles also use it for many differing reasons. There are many myths about the use of nitrogen with some saying it is a stupid scam, and others saying it's a wonder drug for tyres. Neither is correct, but it's not a money making scam. It has sound scientific reasons for it's use, and it can have big advantages for the owners of some vehicles. But it won't benefit some people due to the climate where they live (not good to use in hot dry climates as little advantage), what they drive or ride, how they ride, and what they expect to achieve from it's use. The main advantage is the stabilisation of tyre pressures hot or cold, as these should virtually remain the same if Nitrogen is used. So it's important to set the tyre pressures correctly in the first instance. Depending on vehicle and tyres being used this may be at just under the maximum hot temperature when the tyre is cold, NOT the manufacturers cold pressure. I recommend anyone using it should take professional advice on the correct pressures to use. Otherwise you will find the bike or car may not handle or perform correctly. The great thing is that it can enhance tyre life. But for most that is not the primary reason to put Nitrogen in the tyres. Gains on extra tyre life are minimal. As a side note, the Uk CAA states Nitrogen has to be used in commercial aircraft by law. It is not obligatory for private aircraft to use it unless over a certain size or of a certain type of aircraft. It prevents rapid expansion of tyres at high altitude and rapid deflation at low altitudes, thus lengthening the life of the tyres and in the case of an accident, reducing fire risk. The military of course would use it. So by excluding just that 20% or so of oxygen, it stabilises the tyre pressures, can lengthen tyre life, and may improve fuel economy by making sure the user isn't driving on under inflated tyres, also reducing fire risk in aircraft. But for most of us, the gains are probably very small or almost non existent regarding tyre wear and fuel consumption improvements. It's the pressure stabilisation that is the benefit.

In the main Nitrogen does not expand in the same way Oxygen does in the tyre environment. To keep it simple ignore the other small amounts of trace gases in the air, and the moisture content, they are important but not here. Charles Gas Laws still apply, so Nitrogen does expand but by very little compared to Oxygen in a tyre environment. By using pure Nitrogen, as your tyre heats up the pressure remains largely stable with almost no expansion to note. In the cold weather, your tyre pressures will remain fairly constant too. Very little need to ever top up in very cold weather. Incidentally, as some will know, the oxygen levels in the air are falling. It's no longer at 21% total of the air we breath. It's fallen steadily for the last decade or more due to too many people riding their scooters!!! It's now less than 20% of the air we breath. They reckon it's the forests and the sea (it supplies most of our oxygen) being damaged/poisoned and producing less of the life sustaining stuff along with our increased consumption of it. Grim eh!

If anyone is going to use Nitrogen, it's important to purge the air and most of the moisture from your tyres before filling. We used to do this using a Nitrogen chamber, just a small airtight blast proof box able to take a big wheel in it with a maxalon blast proof side you could see through. It had thick rubber gloves cut into the maxalon to allow you to put your hands in and work on the wheel in an airtight environment. It isn't actually a requirement to have that but you get a better result and waste less gas. It took just an hour to make. Just overfill the tyre to a safe level with Nitrogen and let the customer let out the gas he doesn't need once on the vehicle.

This is not a complete scientific explanation but is in the main 'how it works'. Yeah...I know, droning on and on disease is showing. Sorry bout that...

[ba249k]

W.T.F.
Come on guys, we are riding small engined scooters around!
Let's live in the real world.
All I was saying is that at £1.50 a wheel it is worth a try.
I think some on here are taking life a bit to seriously, even when we were using it in the race car tyres we didn't exam it to this level if it worked great!
Too much other stuff to worry about!!!