R36 - Nitrogen

[Preen59]

I'm confused... - "a hell of a difference"... "useless in cold weather"... "never even bothered trying it in wets"... "went back to normal air"... "couldn't justify the expense"... "marginal advantage"... "quite a noticeable difference"...

Or is it you that seems confused? LOL...

Read what i wrote, don't read between the lines. The difference to the way the tyre reacts is massive. As far as consistency it wasn't really any better if you had the setup sweet and didn't drive the tyres off it. My point was that very noticeable change. I haven't said it was a hell of a lot better.

Different doesn't have to mean better or worse, it's just different.

[Treza360]

For what it's worth I'm running Nitrogen. It's been two months now and my pressures haven't dropped at all.
Economy may have improved but that could be due to a number of factors so i'm not sure but I have had a noticeable drop recently.
Another member on here has also mentioned that one of his rims couldn't hold its' pressure at all and putting Nitrogen in this fixed it. This is meant to be due to the molecular size of pure nitrogen being much bigger than normal air.
Cheers,
Trent

[gregozedobe]

So the consensus seems to be :

1 In certain, specific circumstances (eg racing, aircraft) Nitrogen fill for tyres can be worthwhile.

2 Most people believe that the circumstances in 1 (above) don't extend to normal road tyres in normal road use.

3 Nitrogen fill is unlikely to make much difference to fuel economy (unless the tyres were underinflated before the nitrogen fill)

4 People on this forum like to argue (a lot)

5 Mods on this forum don't like people being rude or insulting when they argue

[Swallowtail]

I agree with 1 to 4...

5 though needs to be rewritten to say that "Mods on this forum don't like people using obscene language insulting other members that breaches forum rules... "

[Maverick]

RACQ have an article that is IMO pretty well spot on, there are heaps of other articles and some much more technical but they mostly have the same conclusions.

http://www.racq.com.au/motoring_advi...ogen_for_tyres

Nitrogen for Tyres
The subject of using nitrogen to inflate car tyres has received considerable publicity over the past few years; particularly since some tyre retailers have begun promoting its supposed benefits.

It is well known that nitrogen gas has been used to inflate the tyres of racing cars, aircraft and heavy commercial vehicles for some time. However it is only relatively recently that it has come into use in normal passenger cars.

So what is nitrogen?
Nitrogen is a colourless, odourless, tasteless, and non-toxic gas that forms about 78% of the Earth's atmosphere. The benefits claimed for using nitrogen over compressed air for inflating tyres are that it:

Reduces the tyre's running temperature
Improves the ride quality
Increases tyre life
Keeps tyre pressures more constant
Slows the rate of pressure loss
Doesn't react with the tyre and rim materials
The following is a discussion of these points.

Reduces the tyre's running temperature
While there is some truth in this statement, the difference relates to the moisture content of the inflation gas rather than the use of nitrogen per se. In fact, dry compressed air will also produce a cooler running tyre. It's also only likely to be of benefit in cases where the tyres are operating at or near their maximum load and/or speed capacities.

Nitrogen improves ride quality
No explanation has been offered as to why this should be the case. There should be no significant difference in the way air and nitrogen behave at normal tyre operating pressures and temperatures.

Nitrogen increases tyre life
A tyre's operating temperature plays a part in how rapidly it will wear. A reduction in temperature at high speeds and loads will be beneficial. However claims by some supporters that nitrogen will double tyre life are questionable.

Reduced pressure build up
The reason that tyre pressures should only be checked when cold is that the tyre’s inflation pressure increases in relation to temperature. Nitrogen is claimed to provide a more stable pressure range in relation to tyre temperature. However once again the moisture content of the inflation gas plays a bigger part than the gas itself. Any benefits are likely to be achieved only under heavy load and/or high-speed conditions.

Pressure loss is slower with nitrogen than with air
Tyre liners and tubes are to some degree porous, and as a result air will eventually leach out. Hence the need to regularly check tyre pressures. Nitrogen, due to its chemical structure, is slower to leak out than compressed air. Therefore the pressure loss is slower. However that doesn't mean that regular pressure checks can be neglected as there is still the possibility of a puncture or some other form of slow leak.

Nitrogen doesn't react with the metal wheel rim or the tyre materials
Probably true. The presence of oxygen and moisture inside the tyre can cause oxidisation (rust) of the metal components. There is also a suggestion that air reacts with the rubber of the tyre itself, however it is not clear if this is detrimental or in any way reduces the life of the average car tyre. Because nitrogen is an inert gas and because it is dry, this problem is, in theory, eliminated. However, unless the tyre is evacuated (i.e. the air is removed) before the nitrogen is added, there will still be some air and possibly moisture in the tyre.

Disadvantages of nitrogen
Nitrogen also has a few disadvantages that should be taken into account. These include:

Cost
Maintenance
Availability
Cost
The typical charge for nitrogen is between $5 and $10 per tyre for a passenger car.

Maintenance
Once your tyres are filled with nitrogen it's important that only nitrogen is used for top up purposes. Adding normal compressed air will negate any benefits of the nitrogen.

Availability
Nitrogen simply isn't readily available everywhere. It's generally restricted to specialist tyre dealers.

A few things to consider
The earth's atmosphere is comprised of roughly 78% nitrogen and 21% oxygen with a few trace gasses mixed in, so when you fill your tyres with compressed air, you are getting about 78% nitrogen anyway.

Not all aircraft use nitrogen in their tyres. In fact generally only larger aircraft with high altitude capability and high landing and take off speeds and high loads use it. The reason given by the Civil Aviation Safety Authority to support its use is that nitrogen, being an inert gas, reduces the risk of high altitude tyre explosions that could damage or destroy an aircraft. Obviously this is hardly a consideration for the average passenger car operator.

Nitrogen is also sometimes used in the tyres of vehicles that operate in potentially hazardous areas, such as mines, to reduce the risk of fire. It is also commonly used in off-highway vehicles where the tyres operate at their maximum load and are highly stressed.

A number of tyre manufacturers have produced position papers on nitrogen, as has the Australian Tyre Manufacturers Association. Some tyre manufacturers have declined to comment. Most have indicated that tyre warranties will not be affected by the use of nitrogen.

Summary
While using nitrogen in passenger car tyres may produce some benefits in some applications, it is questionable if the average motorist will derive any measurable benefit from its use.
Using nitrogen does not remove or reduce the need to check tyre pressures as the risk of a puncture or a slow leak is not altered.
Many of the benefits claimed of nitrogen could be achieved by using dry compressed air from a properly designed and maintained compressed air system.
Nitrogen cannot replace regular maintenance. Regardless of what inflation gas is used, maximum tyre life will only be achieved if the vehicle and tyres are properly maintained. That means regular checking of tyre pressures, wheel balance and alignment.
Should you require further assistance please phone our Technical Advisory Department on (07) 3666 9148 or from outside the Brisbane area on 1800 623 456.

[apom]

Maybe it was Helium instead of Nitrogen thus making the downforce on the road less and therefore reducing the drag and hence better fuel economy!

[Maverick]

A few more links

Nitrogen in car tyres latest evidence that marketers believe a fool is born every minute

Snake oil in your tyres

Is it better to fill your tires with nitrogen instead of air?

Fill 'er Up - - With Nitrogen

Should I use nitrogen in my car tires?

And I can't remember where I found this but may be of interest.

"Putting N2 in tyres has more to do with that you can charge lots of $$$ for N2, but not for air.

N2, being a smaller molecule, diffuses out faster. Having less weight, it also improves handling as there is less rotating mass - but not by much. If we assume a tyre has a volume of about 24 litres and is at 2.5 atmospheres pressure, then the weight of dry air in it will be 72.5 grams. (with air at 80% relative hummidity, it will be about 71 g). Fill it with N2, and it will weigh 70 grams. So you save a whopping 2.5 grams out of maybe a total tyre weight of 10 kg. Olympic cyclists fill their tyres with He to save a few grams - but then a few grams means 0.01 second which might be the difference between a medal or not.

A gram or so of ice in the tyre may cause issues, providing you drive around corners at 300 km an hour within a few seconds of starting the car and before it has melted and evaporated.

As the tyre warms up, the air or nitrogen will expand. If the tyre is at 20 C and then warms up to 40 C, then the air or nitrogen will expand by 1-((273+(40-20))/273) = 0.07 or 7%. If the tyre is at 35 psi at 20 C, it will increase to 37.5 psi at 40 C. Filling with different gases will make no difference as they all expand the same amount if raised by the same amount. If anything, using a denser gas such as S8F will take longer to heat up due to the higher specific heat (amount of heat required) to take it from 20 to 40 C (or whatever) but then will stay warmer longer."

[G-rig]

One of the guys at Bob Jane today were mentioning Nitrogen when I went in for a rotate & alignment, and it didnt take me long to say 'Normal air is fine' and they didn't even mention the price.

They claimed you don't need to check your tyres for 6 months, but it's pretty easy to see it's just a money making idea.

[richdave]

Nitrogen charging of tyres....


God's way of saying you have money to burn

[richdave]

N2, being a smaller molecule, diffuses out faster. Having less weight....

Sorry Maverick, but while Nitrogen has a lower molecular weight, 28 Vs O2 with 32, the molecule size is actually larger thus it does not permeate thru the rubber walls as fast as O2.

And the science behind it...Link