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Filling Tyres with Nitrogen
AndyW - 21/1/11 at 03:27 PM

I'm patiently sitting in Kwik Fit and curiously noticed the following special offer.

Have your tyres filled with Nitrogen. This will increase tyre life by up to 25%. Improved road holding and handling. Increase fuel economy by up to 5%.

And all this for only £1 per tyre.

Now I know that to claim these figures they must have some sort of test data available. But just wondered what us locosters think of these claims and is there really a benefit. Or is it just another consumer "con" to make us part with even more hard earned cash.

Comments and thoughts below please.

One question I think I will ask is what happens if I get a slow puncture and need to inflate my tyre at the road side (garage forecourt) will this affect stability etc.....

blakep82 - 21/1/11 at 03:32 PM

well, i think nitrogen isn't affected by heat changing the tyre pressure, so, if its hot, like summer, and the tyre temperature is hot, i guess normall air may slightly over inflate the tyre, if you do a lot of milage, the middles 'might' wear a bit quick, likewise, if its winter, they might be under inflated, meaning they 'might' affect economy, and wear...

F1 tyres are filled with nitrogen i think.

think the pressures are a bit more stable. think thats it really

loggyboy - 21/1/11 at 03:33 PM

Fairly simple benefit, you wont have to check you tyre pressures for a lot longer. (nitrogen molecules are bigger and dont escape over time like regular 'air'.)
So the only savings are in the fact that your tyre will be at optimum pressures for longer.

[Edited on 21/1/11 by loggyboy]

interestedparty - 21/1/11 at 03:37 PM

quote:
Originally posted by blakep82
well, i think nitrogen isn't affected by heat changing the tyre pressure, so, if its hot, like summer, and the tyre temperature is hot, i guess normall air may slightly over inflate the tyre, if you do a lot of milage, the middles 'might' wear a bit quick, likewise, if its winter, they might be under inflated, meaning they 'might' affect economy, and wear...




Boyle must be spinning in his grave.

blakep82 - 21/1/11 at 03:42 PM

quote:
Originally posted by interestedparty
quote:
Originally posted by blakep82
well, i think nitrogen isn't affected by heat changing the tyre pressure, so, if its hot, like summer, and the tyre temperature is hot, i guess normall air may slightly over inflate the tyre, if you do a lot of milage, the middles 'might' wear a bit quick, likewise, if its winter, they might be under inflated, meaning they 'might' affect economy, and wear...




Boyle must be spinning in his grave.


yeah, well, he's dead
i take it thats not right then? it what i understood of F1 cars using nitrogen when i heard it years ago lol

edit:
yeah!
Formula One tyres are normally filled with a special, nitrogen-rich air mixture, designed to minimise variations in tyre pressure with temperature. The mixture also retains the pressure longer than normal air would.
http://www.formula1.com/inside_f1/understanding_the_sport/5283.html

simailar sort of thing
http://www.whatprice.co.uk/car/nitrogen-tyre-inflation.html

[Edited on 21/1/11 by blakep82]

Richard Quinn - 21/1/11 at 03:45 PM

Nitrogen is actually slightly lighter than air so think of the unsprung weight saving

The only real "advantages" for road cars would be that they should stay at pressure longer and there would be less corrosion of the wheel.

CNHSS1 - 21/1/11 at 03:52 PM

it is correct, nitrogen heavy content to reduce pressure fluctuation affected by heat build up (or lack of). In race car usage, the tyres used have to be 'dried' internally, Longacre and others make some expensive tyre driers that suck the air out, dry the tyre inner and refill with high nitrogen content 'air'. Over a race weekend they can change as race tyre sidewalls can be porous and leak, so unless topped up and checked regularly its a bit pointless. On your daily thats stands out in all weathers and runs for thousands of miles its impractical as when you check/top up your tyres with a service station airline, the 'benefit' is lost.

Great marketing, and based on fact, but think Kwik fit are taking the pi55 personally

Liam - 21/1/11 at 03:52 PM

Bear in mind the air we normally put in is about 80% nitrogen in the first place! There may be some gains but it's hardly a panacea for automotive tyres.

It's supposed to leak slower as N2 molecules are larger than O2, but I dont think the difference is much at all, and as above you already have 80% nitrogen anyway, so how much difference can it make?

Another claimed benefit is the lack of O2 means your tyres corrode (oxidate) slower. Sure, but how do you keep all that O2 away from the outside of the tyre? And when was the last time you replaced a tyre due to oxidation of the internal surface of rubber and not just having the tread worn off due to normal use?

Pressure may be a little more stable with temperature, not necessarily due to the N2, but more the lack of other rubbish that would be in compressed air. Can't be a large effect at all, but must be worth at least a tiny bit or racing cars and planes etc wouldn't bother doing it. So whilst not in quite the same category as pure Snake Oil, for joe public's tintop it's a total load of nutsack bs hype and a great money-spinner for garages offering the service and insisting you always go back to them for top-ups. Personally I'll stick with the 80% nitrogen for free!

[Edited on 21/1/11 by Liam]

scutter - 21/1/11 at 04:04 PM

I think stable temps therefore pressures would be of benefit to us, at a push the enriched air is likely to have less mositure in it so less chance of corrosion!!

We inflate aircraft tyres with pure nitrogen as it's less likely to explode when/if the brakes get too hot as ther is no oxygen present.

ATB Dan.

britishtrident - 21/1/11 at 04:12 PM

Formula 1 cars use a gas containing 80% nitrogen in the tyre gas ---- ie air.


More Snake Oil here -----

LPG Broquet Fuel catalyst Flashlube replacement (R15) on eBay (end time 23-Jan-11 10:34:59 GMT)

phoenix70 - 21/1/11 at 04:19 PM

I'm may be being stupid here but how do they get the air out to put the nitrogen in?

Daddylonglegs - 21/1/11 at 04:20 PM

Not sure why but when I was in the Mob we always filled aircraft tyres using Nitrogen, I guess it's for all the reasons stated anove and others?

Peteff - 21/1/11 at 04:23 PM

I also wondered how the one with the little ball bearings in the tyre could do away with the need for balancing. They would surely just go anywhere in the tyre not necessarily to the point where they are needed when the tyre spins up.

CNHSS1 - 21/1/11 at 04:33 PM

quote:
Originally posted by phoenix70
I'm may be being stupid here but how do they get the air out to put the nitrogen in?


http://www.intercomp-racing.com/Products/TIRE_DRYINGPURGING_SYSTEM_737.cfm

scutter - 21/1/11 at 04:34 PM

I know the C17 uses nitrogen molecular sieve to trap the nitrogen molecules and allow the oxygen which is smaller to pass, the nitrogen then gets compressed for use later.

ATB Dan.

gingerprince - 21/1/11 at 04:40 PM

quote:
Originally posted by Peteff
I also wondered how the one with the little ball bearings in the tyre could do away with the need for balancing. They would surely just go anywhere in the tyre not necessarily to the point where they are needed when the tyre spins up.


That sounds like the old "stick some wet paper in your propshaft to balance it" bullsh1t

40inches - 21/1/11 at 04:57 PM

So! over inflate your tyres by 20%, leave to simmer, when the 20% 02 has escaped, pure nitrogen
in tyres! Simples

Ninehigh - 21/1/11 at 05:11 PM

quote:
Originally posted by 40inches
So! over inflate your tyres by 20%, leave to simmer, when the 20% 02 has escaped, pure nitrogen
in tyres! Simples


That's what I was thinking, if it's just the O2 that's escaping, and we're filling with 80%N (and call it 20%O2) then the % volume of N must be getting higher in each tyre by each inflation

Daddylonglegs - 21/1/11 at 05:19 PM

With the thought about weight reduction, why not fill them with helium? It's lighter, and another benefit is that if you breakdown at the roadside you can cop a lung full of helium from the tyre, won't sort the breakdown, but at least you can have a laugh while your waiting for the recovery wagon

cliftyhanger - 21/1/11 at 05:26 PM

too small, will disappear out the tyres PDQ. Well, much faster than air anyway.

cliftyhanger - 21/1/11 at 05:29 PM

Now, can anybody enlighten me how nitrogen is more pressure stable than other gasses. After all, I have always believed that for a fixed amount of gas, the pressure is proportional to the (absolute, ie degrees K) temperature. Is somebody saying nitrogen doesn't obey this?

Daddylonglegs - 21/1/11 at 05:30 PM

This thread is starting to sound like one of those 'steering geometry' discussions on the LocostUSA forum!

Confused but excited. - 21/1/11 at 05:50 PM

quote:
Originally posted by cliftyhanger
Now, can anybody enlighten me how nitrogen is more pressure stable than other gasses. After all, I have always believed that for a fixed amount of gas, the pressure is proportional to the (absolute, ie degrees K) temperature. Is somebody saying nitrogen doesn't obey this?


It's more stable because it is absolutely dry, whereas atmospheric air has water vapour in it which expands hugely when heated. ie Water when turned to steam = 1700 times the volume. Bit of an extreme example I know but you get the idea.

Also, about helium; "too small, will disappear out the tyres PDQ. Well, much faster than air anyway."

You could always squirt a little glue into the tyres to make the helium atoms stick together.

belgian2b - 21/1/11 at 07:07 PM

Hello,
i have been working for an industrial gaz company for almost ten years before switching for the medical department.

We deliver Nitrogen Nitrogen for tyres, but the most part of the deliveries are made for truck tyres.
there is also some tyres where the manufacturer takes no garanty if the tyre is not filled with nitrogen.

The most important of it is that Nitrogen is more stable thenn air.
So , there is less corosion inside the tyre, the rubber of the tyre is less oxydated byt the air, and the temperature is more stable.
But you nly see those advantages when the tyres stays hot ( like a truck that is driving durning all day).
On tin top cars,most of the time your tyres have not enough time to warm.So nitrogen is not necesary.

For race car, what is important is the stability of the pressure.
When you have 300 gram difference with air in a tyre like cr500 or 888, difference will only be around 50 to 100 gram with nitrogen.



Gerardo

greggors84 - 21/1/11 at 07:56 PM

As has been said, the main benefit in racing is nitrogen doesnt hold as much moisture than air, especially when you compress it air holds alot of water. This means that the pressure increases from the temperature rise is more consistant and repeatable, with tyre pressures being so important its a major benefit having repeatable results with a tenth of a pound.

We use a cheap vacuum device from RS to purge our tyres and are pretty happy with the results, we have heard of other teams purging, filling with nitrogen, purging again and refilling.

Cooper tyres claim that their compressor gives out completely dry air so alot of British F3 teams dont bother with nitrogen.

craig1410 - 21/1/11 at 10:27 PM

Here's what the AA have to say on the matter:
http://www.theaa.com/motoring_advice/safety/filling-tyres-with-nitrogen.html

I got my Locost tyres filled with Nitrogen for free by the tyre fitter who mounted them. We were just blethering away about cars while he fitted the tyres and at the end he looked over his shoulder and since his boss wasn't looking he filled them with Nitrogen for me. Nice man.

They certainly do hold pressure much better than air filled tyres. When they were inflated I got them blown up to 30psi which made moving the car easy while I was finishing the build. I then let them down to 18 or so when ready for the road. I don't think I've had to put any more air in them in over 2 years despite regular checks.

Here's another link for a non-believer:

http://www.tyresave.co.uk/nitrogen.html

And here is the company who make the machines that Kwik Fit use:

http://www.uniflate.com/

I think the key thing is to get DRY air in your tyres. This is easier with Nitrogen and for this reason I would happily spend an extra £1 per tyre to get them inflated with it. It's the price of a decent car wash to get all tyres done so not worth worrying about. Regardless of how much better it is, I think it is clear that it is no worse and is very likely to give some sort of benefit, however small. We are building performance cars after all and for 10% of the price of an oil change I think this is worth it.

Cheers,
Craig.