- Thread starter gordon stephenson
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mike os
just a little insane.....
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nitrogen is used as it is less responsive to temperature... ie pressures stay more constant, and it really is marginal. F1 and the like trying to gain every last gramme of performance, couple of psi & you are off the pace.
in aircraft (if true) it is more likely to be for similar reasons ie ultimate 0.001% more reliable/grip/leak etc given the relatively large temp & pressure differences they are subject to in flight. |IN the event of fire the tiny amount of O2 in an air mix compared to the "saving" using nitrogen in a "normal" atmosphere would make no appreciable difference at all.
in aircraft (if true) it is more likely to be for similar reasons ie ultimate 0.001% more reliable/grip/leak etc given the relatively large temp & pressure differences they are subject to in flight. |IN the event of fire the tiny amount of O2 in an air mix compared to the "saving" using nitrogen in a "normal" atmosphere would make no appreciable difference at all.
I used to use nitrogen in the tyres on my race bike as it gave more consistant pressures when the tyres were hot and the psi increse from cold to hot was less meaning if you spent to long on the grid wating to start although the tyres would have cooled down they would be nearer the optimum pressure so although you have less grip the 'feel' doesnt change too much.
Cold underinflated tyres were horrible to ride on.
Cold underinflated tyres were horrible to ride on.
Omniata
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Your having a laugh?!
Only problem with Helium being the higher passivation through rubber of the gas lol...
Pete.
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I just know you're joking there but in any case it's unsprung mass you need to reduce i.e. the momentum of rotating/reciprocating parts. Using a lighter gas would technically achieve this but the mass saved would be incredibly small.
trouble is you just know some big race team somewhere has tried it to see about how well it works
trouble is you just know some big race team somewhere has tried it to see about how well it works
"Fer Chrissakes, don't tell Rubens!"
rtcosic
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Inflating Tyres with Nitrogen
Whilst doing some research on Driver Distraction I tripped over some reliable research on the benefits of inflating tyres with nitrogen:
US National Highway Traffic Safety Administration Vehicle Research and Test Center (sic) Report DOT HS 811 094.
Link
The three arguments I have heard for use of Nitrogen are:
The Answers?
Holding pressure:
“It should be noted that inflation with nitrogen merely slows the rate of diffusion of gas from the tire (sic) and is not a substitute for regularly maintaining tire (sic) pressure.”
If you DO keep the pressure regularly topped up with air, after a year or so they will have about 90% Nitrogen in them anyway as the Oxygen diffuses out!
I can’t say that excites me very much!
Better fuel economy:
“The study indicated that inflating with nitrogen in place of air had no immediate effect on laboratory tire (sic) rolling resistance. However, it is estimated that at the end of 90 days of on-vehicle service with no inflation pressure maintenance, the improved retention of inflation pressure using nitrogen versus air inflation will result in a 1.5-percent reduction in tire (sic) rolling resistance.”
So NO direct benefit, but if you don’t maintain your car the nitrogen filled tyre will lose pressure more slowly, and it’s the loss of pressure that increases rolling resistance.
So another ‘meh’ from me.
Longer life:
They aged the tyres; “these oven aging conditions replicate approximately 2.5 years and 47,000 kilometers (sic) (29,000 miles) of service in the high ambient temperatures of the Southwestern United States, or as much as double that amount of service in the northernmost States”
5 years and 58,000 miles!
They did find some benefit in the use of Nitrogen on aging, but not much.
Americans seem to expect tyres to last 50,000 miles on their everyday cars and the southern states are hot too, so that could be significant for them. I wear out the tread on my tyres within 2 to 3 years, so that’s another ‘meh’ for me.
I conclude that if the tyre fitter fills my new tyres with Nitrogen for free; then thanks I’ll have it. It certainly won’t do any harm. But I won’t pay for it.
The other little factoid was that 1psi under inflation costs 0.2mpg or thereabouts.
By the way they tested 261 tyres of 30 different types.
Whilst doing some research on Driver Distraction I tripped over some reliable research on the benefits of inflating tyres with nitrogen:
US National Highway Traffic Safety Administration Vehicle Research and Test Center (sic) Report DOT HS 811 094.
Link
The three arguments I have heard for use of Nitrogen are:
- Nitrogen diffuses through the tyre wall more slowly than oxygen, so the tyres hold their pressure better.
- Nitrogen filled tyres have lower rolling resistance so will save fuel.
- Oxygen degrades the tyre so using Nitrogen the tyres will last longer.
The Answers?
Holding pressure:
Air filled tyres lost on average 2.13%/month
Nitrogen filled tyres lost on average 1.39%/month
Sounds good at first, but if you have a car tyre that should be inflated to say 32 psi (220kPa, 2.2bar); this translates into 0.68 psi/month for air and 0.44psi/month for Nitrogen. So if you assume you don’t want your tyres to be more than 1psi low, this means your pressure check interval can be reduced from once every 44 days to once every 68 days.Nitrogen filled tyres lost on average 1.39%/month
“It should be noted that inflation with nitrogen merely slows the rate of diffusion of gas from the tire (sic) and is not a substitute for regularly maintaining tire (sic) pressure.”
If you DO keep the pressure regularly topped up with air, after a year or so they will have about 90% Nitrogen in them anyway as the Oxygen diffuses out!
I can’t say that excites me very much!
Better fuel economy:
“The study indicated that inflating with nitrogen in place of air had no immediate effect on laboratory tire (sic) rolling resistance. However, it is estimated that at the end of 90 days of on-vehicle service with no inflation pressure maintenance, the improved retention of inflation pressure using nitrogen versus air inflation will result in a 1.5-percent reduction in tire (sic) rolling resistance.”
So NO direct benefit, but if you don’t maintain your car the nitrogen filled tyre will lose pressure more slowly, and it’s the loss of pressure that increases rolling resistance.
So another ‘meh’ from me.
Longer life:
They aged the tyres; “these oven aging conditions replicate approximately 2.5 years and 47,000 kilometers (sic) (29,000 miles) of service in the high ambient temperatures of the Southwestern United States, or as much as double that amount of service in the northernmost States”
5 years and 58,000 miles!
They did find some benefit in the use of Nitrogen on aging, but not much.
Americans seem to expect tyres to last 50,000 miles on their everyday cars and the southern states are hot too, so that could be significant for them. I wear out the tread on my tyres within 2 to 3 years, so that’s another ‘meh’ for me.
I conclude that if the tyre fitter fills my new tyres with Nitrogen for free; then thanks I’ll have it. It certainly won’t do any harm. But I won’t pay for it.
The other little factoid was that 1psi under inflation costs 0.2mpg or thereabouts.
By the way they tested 261 tyres of 30 different types.
pidgeon chit welder
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Point No 3 was a thing that hit home when I was present at a Nat tyre place
getting my two front tyres replaced ( have to do it at almost every 10,000 miles with the new tyre compounds ) .
Thank goodness it is all done under the motability contract.
The lady sitting next to me was having a full set and spare on her Porsche Boxter.
She was asked if she would like nitrogen in the tyres and carefully listened to the benefits of £3.50 worth of nitrogen ." Yes please "she said .
I asked her why she said nitrogen and she said " It costs just over £1500 for my tyres , I'm quids in at only a 1% tyre life extension ".
Note this last set of Nitrogen filled tyres on my Sedona ...same brand as before (fitted 9300 miles ago ) are not showing the same wear as the standard air filled ones . I'm almost up to 70K and would have been needing a new front set by now,
getting my two front tyres replaced ( have to do it at almost every 10,000 miles with the new tyre compounds ) .
Thank goodness it is all done under the motability contract.
The lady sitting next to me was having a full set and spare on her Porsche Boxter.
She was asked if she would like nitrogen in the tyres and carefully listened to the benefits of £3.50 worth of nitrogen ." Yes please "she said .
I asked her why she said nitrogen and she said " It costs just over £1500 for my tyres , I'm quids in at only a 1% tyre life extension ".
Note this last set of Nitrogen filled tyres on my Sedona ...same brand as before (fitted 9300 miles ago ) are not showing the same wear as the standard air filled ones . I'm almost up to 70K and would have been needing a new front set by now,
Pete.
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What pressures do you use in your Sedona? When we bought ours I found the steering to be heavy & vague, checked the tyre pressures and they were correct according to the plate (somewhere in the 30psi-range).
I have a works van that is almost identical in size & weight to the Sedona, uses the exact same size tyres with the same ply rating but the working pressures were in the 50's and 60's. I pumped the Sedona tyres up to 50psi and the steering & handling were totally transformed. Been like that now for 3 years, no handling issues wet, dry or whatever and no funny wear problems with the tyres but the steering is much lighter and more positive.
Filled with air though, not nitrogen
pidgeon chit welder
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What pressures do you use in your Sedona? When we bought ours I found the steering to be heavy & vague, checked the tyre pressures and they were correct according to the plate (somewhere in the 30psi-range).
I have a works van that is almost identical in size & weight to the Sedona, uses the exact same size tyres with the same ply rating but the working pressures were in the 50's and 60's. I pumped the Sedona tyres up to 50psi and the steering & handling were totally transformed. Been like that now for 3 years, no handling issues wet, dry or whatever and no funny wear problems with the tyres but the steering is much lighter and more positive.
Filled with air though, not nitrogen
Just checked my hand book to be sure all figures agree ,mine are 36 psi all round cold ..long journeys of 100 mile or more up at 38 psi . I observed that the pressures got to 46 psi hot when driving down to St Tropez towing a 1400 kg caravan two years ago but that was in air temps of 40 ( ish ) oC and on tarmac of higher temps ..the tyre rubber would have softened & expanded to accommodate them.
I'd say if you were involved in an accident and your TP's at 50 psi were checked you could be held liable for having an unsafe vehicle and all that results from that.. 50 psi cold does alter the braking characteristics and general handling.
Pete.
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Yeah I've heard that argument several times. Mostly from people who haven't thought what they had just said through properly. Manufacturers don't always get it right and their pressures are only 'reccomended' anyway. Also, the tyre pressures they quote are for the make they fit as OEM. Different tyre manufacturers specify different pressures for their tyre for the same model of vehicle so unless you have the OEM tyres fitted the figures in the handbook aren't fully relevant.
Under-inflated tyres are a serious hazard and very prone to over-heating and failiure from flex in the tyrewall. I'd wager that easily more than half the cars on the road have at least one under-inflated tyre (as evidenced by the stats earlier in the thread).
Over-inflated ones suffer reduced increases in temperature at speed because the carcass is less flexible. Either way, the simple fact that the road handling is improved so dramatically is enough for me to stick to my 50psi.
Try it mate, pump your tyres up an extra 10psi, drive a couple of miles, make sure you take in a roundabout or two, then let them down again. You won't believe the difference.
Under-inflated tyres are a serious hazard and very prone to over-heating and failiure from flex in the tyrewall. I'd wager that easily more than half the cars on the road have at least one under-inflated tyre (as evidenced by the stats earlier in the thread).
Over-inflated ones suffer reduced increases in temperature at speed because the carcass is less flexible. Either way, the simple fact that the road handling is improved so dramatically is enough for me to stick to my 50psi.
Try it mate, pump your tyres up an extra 10psi, drive a couple of miles, make sure you take in a roundabout or two, then let them down again. You won't believe the difference.
pidgeon chit welder
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My beastie is a Motability car and it has OEM tyres and Motability's decided replacements ..approx every 10.000 mile on the fronts. ( Michelin's )
Who am I to wack up the TP ? ..it will be picked up on the vehicle inspections , noted & re adjusted . I have driven oodles & oodles of cars vans of all sizes , S, M , L lorries , crane sets , and the odd tanktransporter etc since 1967. I don't have any problems with the KIA at all , in fact it's one of the best vehicles I've ever driven except for the massive steering circle ..it's like turning a shoe box .
Who am I to wack up the TP ? ..it will be picked up on the vehicle inspections , noted & re adjusted . I have driven oodles & oodles of cars vans of all sizes , S, M , L lorries , crane sets , and the odd tanktransporter etc since 1967. I don't have any problems with the KIA at all , in fact it's one of the best vehicles I've ever driven except for the massive steering circle ..it's like turning a shoe box .
