Ideal Tubeless Tyre Pressure

[ShintaroX]

Retracted.

Edited August 17, 2011 by ShintaroX

[Crosswind]

Whatever you do, never fill your tires with Nitrogen. It doesn't make any kind of big savings as the Nitrogen sellers and idiots like Jami tell us and when you completely deflate your tires to pump Nitrogen, you will end up doing much more harm to the tires than good.

Here's an article from Scientific American about it. The conclusion is its not worth the cost.

http://www.scientificamerican.com/article.cfm?id=nitrogen-filled-tires-fuel-efficiency

(I believe we have argued about Nitrogen before)

Edited August 17, 2011 by Crosswind

[SeanD]

Tire kadey and petrol kadey guys in SL don't know jack about correct tire pressure. Hence why 90% of the cars on the road seem to be severely under inflated. And if they LOOK under inflated then they are really really underinflated, cos even when it's at its ideal wait it looks a bit down. Please do a search on this thread, there's plenty of info on how to measure, when to measure, effect of the heat of the road on the reading, etc. It's only when there's a lot of high speed blowouts on the new expressway that people may finally realise.

[techlove]

Something's missing here.

Talking about tyre pressure should be 28,29 ,30,35...so on but no one's talking about their tyre size?

Air preasure differs with the tyre size right?

I would say go with your car manufacturer's specifications.The guys who made your car definitely know better than you,me,the most proffessional local mechanic and the tyre kade guy.

I have 195-65-15 tyres and according to the manufacturer I use 35psi and it's totaly fine.

[ShintaroX]

Something's missing here.

Talking about tyre pressure should be 28,29 ,30,35...so on but no one's talking about their tyre size?

Air preasure differs with the tyre size right?

I would say go with your car manufacturer's specifications.The guys who made your car definitely know better than you,me,the most proffessional local mechanic and the tyre kade guy.

I have 195-65-15 tyres and according to the manufacturer I use 35psi and it's totaly fine.

You are right, but you also need to take into account the road conditions in Sri Lanka are not what the manufacturer had in mind when recommending a tyre pressure. My recommended pressure is 35psi as well, but I find it bumpy and this affect the suspension over time, so I lowered to 28. As a result the ride is far more comfortable and less wear and tear.

[jami]

Whatever you do, never fill your tires with Nitrogen. It doesn't make any kind of big savings as the Nitrogen sellers and idiots like Jami tell us and when you completely deflate your tires to pump Nitrogen, you will end up doing much more harm to the tires than good.

Here's an article from Scientific American about it. The conclusion is its not worth the cost.

http://www.scientificamerican.com/article.cfm?id=nitrogen-filled-tires-fuel-efficiency

(I believe we have argued about Nitrogen before)

really? how you say never fill with n2 so ur misleading the correct things with a american.

do you know the difference between n2 and air? even when you fill your tire with air, by the time it will end up with n2 after few days with low tire pressure, bcz all the co2 and h2o will leaks.

[Watchman]

really? how you say never fill with n2 so ur misleading the correct things with a american.

do you know the difference between n2 and air? even when you fill your tire with air, by the time it will end up with n2 after few days with low tire pressure, bcz all the co2 and h2o will leaks.

WOW! your stupidity never fails to amaze me! Firstly no matter what you pump in the pressure is ALWAYS the same. Even if you pump your bloody fart gas in! Please dont mislead people!

And when you say "all the co2 and h2o" you make it sound like a lot when its actually less than 2% of 'air'.

[jami]

WOW! your stupidity never fails to amaze me! Firstly no matter what you pump in the pressure is ALWAYS the same. Even if you pump your bloody fart gas in! Please dont mislead people!

And when you say "all the co2 and h2o" you make it sound like a lot when its actually less than 2% of 'air'.

so whats wrong you pump air or n2 for 28 psi thats same. but the volume ratio is different and the weight is different, do you know this? what i say if it is air the pressure will drop by 5 psi.

are you see these things in greek same as ur friend?

be honest rather insulting (as common sense of you people)

[Watchman]

so whats wrong you pump air or n2 for 28 psi thats same. but the volume ratio is different and the weight is different, do you know this? what i say if it is air the pressure will drop by 5 psi.

are you see these things in greek same as ur friend?

be honest rather insulting (as common sense of you people)

You wanna talk math is it. Fine; say you pump air for 28 psi. And you claim 5psi is lost. So 5 out of 28 is nearly 18% (17.8 if u wanna knit-pick). Yes the CO2 and H2O you claim to be the cause for the drop is less than 2%. So where is the remaining 16% lost smart(dumb)ass?

And HOW does weight even matter here? The queston is do YOU know what you're talking about. Just cos you use fancy 'science-y' words doesnt make you smart

PS:

Why dont you explain how this volume ratio and weight difference matter to all those non-greek readers ?

[bud]

use same as 28 it doesn't matter, but if you use air use 30 (it will leaks h2o/co2 when the tire temperature goes up and pressure will go down by almost 5psi) better use n2 for stable pressure and it will prevent the corrosion and even increase stability of breaking

Frankly I asked that question to stop others get mislead by unnecessarily get complicate their minds thinking the composition of air and the difference of that with Nitrogen.

Whatever we fill in to the tire the pressure level we need to keep will not change. If we keep 28 with air simply we need to keep the same with Nitrogen as well. But if we use air for few days the tire pressure level will reduce a bit as water composition of the air will get evaporate. If v check our tire pressure once a week v will notice this. But if we use Nitrogen this reduction will not happen and same pressure level will remain for a longer time.

If the logic is simple as this there will be no point getting complicate our mind unnecessarily.

[g-unit]

28 psi is ok for small cars like Vitz upto the size of an Allion. But for larger cars specially European ones need atleast 30 psi. Larger SUVs and other vehicles need about 30-32 psi. If not the tire wear will be uneven (excessive wear from the sides), mileage gotten out of a set of tires and the gas mileage will be less. Even the handling characteristics of the car will be affected drastically.

[Crosswind]

really? how you say never fill with n2 so ur misleading the correct things with a american.

do you know the difference between n2 and air? even when you fill your tire with air, by the time it will end up with n2 after few days with low tire pressure, bcz all the co2 and h2o will leaks.

Stupid Idiot.

Scientific American is a renowned magazine. It doesn't mean science is only applicable to America. I don't quote any facts from websites owned by businesses to discuss a point and I definitely don't talk off the top of my head like you do.

You are saying yourself that after a few days your tires will end up with Nitrogen even if you pump air. So what are the solutions?

1. Spend 200 rupees to pump Nitrogen, and when you completely deflate tires to do that, risk all kinds of structural damage to the tires, when the whole weight of your vehicle rests on the deformed tires.

2. Check your tire pressure every week or so for free, whenever you go to the shed to pump petrol (which is what I do... from the same shed every week. I have never had the issue of tires losing pressure the way you claim)

Which one of the above, is the best solution to the problem of losing air pressure if you pump air???

You idiot, if you are trying to promote your business of selling Nitrogen, you should find a different forum, where people have IQs less than 10.

Edited August 18, 2011 by Crosswind

[jami]

Frankly I asked that question to stop others get mislead by unnecessarily get complicate their minds thinking the composition of air and the difference of that with Nitrogen.

Whatever we fill in to the tire the pressure level we need to keep will not change. If we keep 28 with air simply we need to keep the same with Nitrogen as well. But if we use air for few days the tire pressure level will reduce a bit as water composition of the air will get evaporate. If v check our tire pressure once a week v will notice this. But if we use Nitrogen this reduction will not happen and same pressure level will remain for a longer time.

If the logic is simple as this there will be no point getting complicate our mind unnecessarily.

correct, but these greek people never understnd it

Edited August 18, 2011 by jami

[jami]

Stupid Idiot.

Scientific American is a renowned magazine. It doesn't mean science is only applicable to America. I don't quote any facts from websites owned by businesses to discuss a point and I definitely don't talk off the top of my head like you do.

You are saying yourself that after a few days your tires will end up with Nitrogen even if you pump air. So what are the solutions?

1. Spend 200 rupees to pump Nitrogen, and when you completely deflate tires to do that, risk all kinds of structural damage to the tires, when the whole weight of your vehicle rests on the deformed tires.

2. Check your tire pressure every week or so for free, whenever you go to the shed to pump petrol (which is what I do... from the same shed every week. I have never had the issue of tires losing pressure the way you claim)

Which one of the above, is the best solution to the problem of losing air pressure if you pump air???

You idiot, if you are trying to promote your business of selling Nitrogen, you should find a different forum, where people have IQs less than 10.

so you prefer air? and never to use n2?

[Simplelife]

so you prefer air? and never to use n2?

Not only Crosswind, most of the sane people around here prefer air instead of N2

[jami]

Not only Crosswind, most of the sane people around here prefer air instead of N2

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.

If I ever need to top off a tire when I'm out on the road, I'll always briefly depress the tire chuck's valve with my thumbnail and vent some air. If my thumb gets wet, there's water in the line. Some gas stations don't do a very good job of keeping the humidity out of their air system. I don't even like to use a water-based tire-mounting lubricant unless I can let the tire bake in the sun for a couple of hours before I air it up and seat the bead. I've dismounted tires (not mine) that had several quarts of water inside—probably from a compressed-air hose that collected water and was never purged properly.

How is water relevant to a nitrogen discussion? Any system that delivers pure nitrogen is also going to deliver dry nitrogen. Filling tires with nitrogen involves filling and purging several times in succession, serially diluting the concentration of oxygen in the tire. This will also remove any water.

It's certainly simple, although time-consuming, for a tire technician to fill and bleed tires. But most shops use a machine that not only generates almost pure nitrogen by straining the oxygen out of shop-compressed air, but will also automatically go through several purge cycles unattended. Some shops have been charging as much as $30 per tire for this service. I think that's too much. If you're buying a new tire, it should be far less. Still, the nitrogen generator, filling system and technician's time aren't free—the dealer is entitled to some return for that.

So, to answer your specific questions: With nitrogen, your tire pressures will remain more constant, saving you a small amount in fuel and tire-maintenance costs. There will be less moisture inside your tires, meaning less corrosion on your wheels. You will not be able to feel any difference in the ride or handling or braking, unless your tire pressures were seriously out of spec and changing to nitrogen brought them back to the proper numbers.

source - http://www.popularmechanics.com/cars/how-to/repair-questions/4302788

Edited August 18, 2011 by jami

[(b_d)wije]

FYI guys-

the tyres of Nissan GTR 2011 spec are filled with pure nitrogen because ordinary air is considered to be too unstable, it expands and contrasts too much!!! (Jeramy Clarkson,2011)

[Crosswind]

so you prefer air? and never to use n2?

Yep... u finally figured it out.

[ShintaroX]

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.

Listen you illiterate, this article just says what we've been saying all along, if you keep air in the tires over the "long-term", then yes, you are losing pressure. But if like most people you check your air regularly, then you won't find significant loss. I check my air weekly and I rarely find air loss more than 1-2 psi, often there is no loss at all. If you are losing 5 psi per week, then you have a hole in your tires. If you want to pay to put nitrogen, please do, as they say "a fool and his money are easily parted".

[Crosswind]

With nitrogen, your tire pressures will remain more constant,

You can achieve the same by checking your tyre pressure every week for FREE, without causing structural damage to tires,when you go to pump petrol to the car.

saving you a small amount in fuel and tire-maintenance costs.

the key-word here is small. How small? maybe waaaay smaller than what you can save by following good driving habits.

There will be less moisture inside your tires, meaning less corrosion on your wheels.

Oh god! I didn't know all us air-pumpers are suffering from corroded wheels!!!

You will not be able to feel any difference in the ride or handling or braking,

Ok so isnt this a point in favour of AIR?

unless your tire pressures were seriously out of spec and changing to nitrogen brought them back to the proper numbers

You can achieve the same by checking your tyre pressure every week for FREE, without causing structural damage to tires,when you go to pump petrol to the car.

So what's the point which is seriously in favour of Nitrogen here???

Edited August 18, 2011 by Crosswind

[Watchman]

So Jami, is the article you quoted written by a sri lankan living in Sri Lanka?

[bud]

correct, but these greek people never understnd it

Jami,

Machng Isn’t that u the person made this topic so complex…?

[vishkid]

Jami - let me know your/your father's/BIL's/etc spot where I could pump my tires with N2 for 200 bucks or whatever .. I want to get my ordinary air pumped tyres deflated and filled with N2, just to compensate for the effort you put in to justifying N2! Your resolve is amazing and I will honor it at the expense of my wallet .. and my common sense.

I hope my N2 filled tyres will last at least a couple of years without checking or pumping air again, as it will take me that long to recover the lost 200 bucks though - hopefully you'll be able to give a guarantee when I pump?

[vishkid]

Also I heard that pumping N2 from Saudi Arabia is better because that air inherently consists of fewer water molecules than Sri Lankan N2 which can hv a bit of a moisture contamination due to our high humidity (even when using the same N2 pumping machine). So I would be extremely grateful if Jami or anyone else can give me a pointer to a place which serves mid-eastern N2, so that I can leave my tyres unattended for 3 years instead of 2!

Cheers

[RWD]

You are right, but you also need to take into account the road conditions in Sri Lanka are not what the manufacturer had in mind when recommending a tyre pressure. My recommended pressure is 35psi as well, but I find it bumpy and this affect the suspension over time, so I lowered to 28. As a result the ride is far more comfortable and less wear and tear.

got to agree with you here. i've pumped 34 for the 15 inch wheels and found the ride impossible on bumpy roads around colombo. as a rule of thumb i stick to 28PSI for wheels up to 15 inch. 16 inch and over, i use 30 PSI. When going outstation and at higher speeds, I increase tyre pressure to about 32.