R36 - Nitrogen

[R36Driver888]

My fellow R36 owners don’t be fooled by the title…

Due to some recent rim damage ( I wish Brisbane had proper drive ways) and that workman cleaned up after themselves as I believe someone in Brisbane is missing a nail..

During the repair the salesman talked up the benefits of using nitrogen to fill up your tyres… I must say at first I did not notice anything but I do now see between a 30 – 45km gain when it comes to refuelling plus it supposed to promote even tyre wear which is a good thing given the replacement cost…

Anyway food for thought my friends.

[Swallowtail]

Call me a cynic, but how on earth can nitrogen in your tyres (assuming a constant given pressure) be proven to improve your fuel economy by 6 - 8%?

As you say food for thought, but nothing I have read to date has convinced me of the value. Just my 0.02...

[R36Driver888]

Call me a cynic, but how on earth can nitrogen in your tyres (assuming a constant given pressure) be proven to improve your fuel economy by 6 - 8%?

As you say food for thought, but nothing I have read to date has convinced me of the value. Just my 0.02...

I am just quoting on what i am seeing on the dials... ( It should be noted that this is not based on city driving ) Brisbane to the GC and back twice a week..

I'ill give you change for you 0.02!

[passatpout]

My old man had nitrogen-filled tyres on his Merc, and didn't notice much of a difference with it running his normal day to day stuff. The big thing was that the tyre caps were green.. but he also wasn't going to go to the hassle of keeping a nitrogen cylinder at home for checking tyre pressures.

There's a few reasons why I reckon it's not worthwhile..

First up, standard, normal, everyday breathing air comprises around 79-80% nitrogen, around 20% oxygen, and the rest is other gases such as carbon dioxide, helium, etc, in trace amounts.

Secondly, the tyres (at least my Dad's) weren't evacuated prior to filling with nitrogen, which means that a fair proportion of the gas within is air, rather than pure nitrogen. I'd also hate to think what damage would be done to tyres if a vacuum was drawn within them anyway.

Finally, from a gas/thermodynamics perspective and ideal gas law, there isn't much difference between air and nitrogen anyway from a behaviour perspective.

[blutopless2]

i think the main reasons for using nitrogen in tyres is...
its dry... moisture in the tyre speeds up degredation.
more pressure stable... less pressure fluctuations and slower migration of gas through the tyre.

[Timbo]

You're noticing a placebo effect...maybe even contributing to it. The reality is that unless you are completing the exact same drive under the same conditions a whole range of factors might be at play. Perhaps previously your tyres were simply under-inflated?

Consider this in relation to nitrogen inflation: for it to have any real effect (given normal air is 73% nitrogen) the tyre fitter will have had to have removed ALL the air in the (deflated) tyre before filling it with nitrogen. In practical terms, that's not easy to do and I'd need to be convinced the corner tyre store had the equipment to do it.

I suspect the 'nitrogen inflation' is a way for tyre stores to gather a few more $s in a low margin business, and that's really the summary of benefits.

[Maverick]

i think the main reasons for using nitrogen in tyres is...
its dry... moisture in the tyre speeds up degredation.
more pressure stable... less pressure fluctuations and slower migration of gas through the tyre.

And those things matter if you're filling a race car or aircraft tyre where you want 100% consistence and cost is not an issue. Not so much a car tyre mounted on an alloy wheel.

In the car as the remaining 20% of the gas leaves the tyre (leaving the nitrogen behind) you refill with more air from the servo which mixes with the now enriched nitrogen content and so on so the tyre should end up a higher proportion of nitrogen each time you fill the tyre.

There is a heap of research available on the interweb that will confirm that nitrogen in cars is a waste of money as it offers no benefits and is just a money maker for the outlets that sell/push the product.

During the repair the salesman talked up the benefits of using nitrogen to fill up your tyres… I must say at first I did not notice anything but I do now see between a 30 – 45km gain when it comes to refuelling plus it supposed to promote even tyre wear which is a good thing given the replacement cost…

The gain will be related to the tyres having more pressure in them than before (ie before you had them refilled they were a lower pressure and/or your driving style changing and/or the engine has settled in). Nitrogen can't offer better fuel economy, your tyre is either inflated to the correct pressure or it's not and it's no substitute for regular tyre checks.

[Preen59]

Ok now i'll have to go back to my Kart racing days..

We tried Nitrogen and there was a vast difference between regular (atmosphere) air and pure Nitrogen.

I was a skeptic too beforehand, considering the fact that ~75% of atmospheric gas is Nitrogen...

It makes a difference- A hell of a difference.

I used it for around 12 months of solid racing at a lot of big meetings etc. What i did was wrap a ratchet strap around the tyre with the valve removed and squash it in as much as i could, to decrease the volume inside as much as possible, refit the valve, then inflate with nitrogen.

What i found was that you would go out with cold tyres (at lets say, 22 in the fronts and 24 in the backs) and normally you would come in at 24/26 hot if you had the setup sweet and the track had some bite. That was as close to cold pressure as you were ever going to get.

Now, throw in some nitrogen.. I found that the hot pressures were generally about .5psi higher than cold, and the tyre was more consistant throughout the session. This meant that you could go out with "hot" pressures and have good grip early without frying the tyres and having them go off mid race.

End result was it worked on a hot day when there was some grip down and was absolutely useless in cold weather on a cold track (never even bothered trying it in wets!). After a while i went back to using normal air again as i really couldn't justify the expense of the bottle rental etc for the marginal advantage it gave me..


Anyways, i don't know what it will do for street tyres as i've never been bothered to try it in them (I think its a waste of time), but it definitely does make a difference and quite a noticeable one.

[Swallowtail]

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...

[Maverick]

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...

You missed "I think it's a waste of time" and "I don't know what it will do for street tyres" and "never bothered to try it"

[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_advice/about_your_car/car_factsheets/nitrogen_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.