Do you use Nitrogen in your tires?

[Jerome Stanek]

Dennis, my wife has nitrogen in the tires on her SUV and I have air in the ones on my truck. The nitrogen have held their pressure for over 3 years (35,000 miles) and I have to check and refill my truck tires every couple of weeks! I notice a difference in handling because of the tires... the nitrogen are firmer and do not seem to be subject to weather changes. My truck tires get flat spots from sitting in the garage overnight - especially in the wintertime - her's do not. Next time I get tires... I will get the nitrogen.

If your tires leak now they may still leak with the nitrogen I had air in my truck and didn't have to add for over 5 years Nitrogen in the suv and had to add about once a year.

[Steve Schlumpf]

Jerome - you are probably right about that! I was thinking more about when I get a newer vehicle... then switching over to nitrogen. Just my personal experience... which could be because of the tires used, wheel material or something else... but the nitrogen has been a lot less hassle for me to deal with.

[Stephen Cherry]

It's true- in the old days, some steel wheels would rust on the inside due to bad paint and water in the air. This is something that I saw back in the 80's with older wheels. I don't think corrosion is a problem with modern wheels though.

As for some tires leaking and others not- some tires have an extra layer of butyl rubber to keep them from leaking, and other cheaper tars do not.

[Robert Delhommer Sr]

Another way to make money. 78% is good enough for me.

[Steve Peterson]

I agree that the claim of 30% better fuel economy is mostly snake oil. Sure you will get better fuel economy with properly inflated tires and 100% nitrogen may leak out slightly slower than 78% nitrogen. If you let 22% of the air out of your tires and drove around like that, then you will get poor fuel economy. All you need to do is re-inflate the tires and you are back to the original state. As long as you maintain proper pressure, you will get the same fuel economy with nitrogen or air. I believe all new cars are required to monitor tire pressure, so there is no difference.

Steve

[Mike Henderson]

It's just marketing. I agree that the most important thing is to keep moisture out of the gas that's put into the tire, whether it's nitrogen or regular air.

Mike

[Dan Hintz]

I noticed Costco, and I think Belle Tire which is one of the major regional players around here use nitrogen at no charge.

Funny you should mention Costco... SWMBO and I signed up there just a couple of months ago because (among other things) they carried the same tires she already had on the car (she blew through a sidewall hitting a curb, and I didn't want to mix/match tires). I didn't know it at the time, but they use Nitrogen exclusively to fill the tires. Last week she was getting her oil changed at the local shop and, per their usual process, they were going to fill up the tires (one was getting low... I know, a tire filled with Nitrogen, getting low... shocker!). They didn't want to do it because they didn't use Nitrogen, and they didn't want to "contaminate" what was in there. She called me, I called "BS", then I told them to swap out the green stem caps for the regular black and "contaminate" away. They didn't swap the caps, but at least the topped off the tires.

Really? You don't want to "contaminate" the Nitrogen with shop air? <sigh>

[David Cefai]

Nitrogen inflation is not available in my country. I am a chemist with 38 years industrial experience. So a lot of what follows is not based on a nitrogen experience.

The nitrogen molecule is a little smaller than oxygen. Consequently it will diffuse out of a tyre faster if that were possible, On the other hand the difference is minimal.

Air contains ~20% oxygen. This oxidises stuff. There is enough oxygen in air to maintain a fire.

Oxygen inside a tyre will oxidise the rubber. Oxygen outside the tyre will also oxidise the tyre! So will sunlight. Exhausr fumes don't do the rubber any good either.

The tendency today is for a tyre to suffer structural failure, from the outside, before the tread wears down to an unsafe level. At least that's what happens in Malta. (Max temp is >100 deg F in summer. Min temp is 36 deg C on a REALLY cold day).

So pumping with nitrogen is essentially a waste of time. To cover some of the other possibilites mentioned in this thread, at the pressures we are considering there is no difference in "compresssibility". Carbon Dioxide would diffuse out of a tyre more slowly than air but why bother?

The water issue could be a major factor in corrosion. The presence of some CO2 in the tyre could make things worse - it could make the water a little more acidic.

I hope this helps.

[Lee Schierer]

Most dealers around here have dropped the nitrogen tire filling scam and just use air. As noted, there is oxygen in the air in the tire before it is pressurized and it is never removed.

The biggest culprit to wheel corrosion and air leakage on tires is clip on wheel weights on aluminum wheels, even the coated clip ones. In the past 10 years, aluminum wheels have become very common on vehicles in order to decrease weight and increase fuel economy. When the wheels are manufactured, they are anodized to protect against corrosion. When they pound on the clip on wheel weights when the tires are balanced, the clips cut through the anodize and leave exposed aluminum in contact with steel. Add a little moisture and some salt and you have a miniature galvanic cell eating your wheel. In northern states where salt is used on the highways in the winters this corrosive action can produce bubbling in the aluminum that eventually will raise the rubber bead enough for air to leak out. Aluminum wheels will leak about a pound per week or more meaning that most people who aren't religious about checking tire pressures are driving on under inflated tires.

Although all new cars come with clip on weights, on all my cars, when I purchase new tires, I insist on stick on wheel weights to stop any additional corrosion. So far it has been a pain to insist, but on my oldest vehicle (2004), The wheels still look brand new where the beads seat and the tires hold pressure for months, which is fine since my service shop checks the air pressure during the oil changes.

[ray hampton]

If your tires get moisture in the tires and it condense to water , DO the water freeze during the cold weather when the car are park overnight ? will the ice cause a unbalance condition ? how long will this ice take to melt at zero temperature ?

[John Stankus]

Another chemist here. Nitrogen should effuse (leak) faster than oxygen by the square root of 8/7. (7% faster) Racing applications of nitrogen is to make sure there is no moisture. Liquid water in the tire will contribute to pressure build when the tire gets hot. ( or greater pressure drop when it gets cold enough to condense out the water)
Carbon dioxide would work fine. I know some auto crossers who have a CO2 tank that they run an impact wrench off of to change tires and to fill the tires to pressure

John

[Dan Hintz]

If your tires get moisture in the tires and it condense to water , DO the water freeze during the cold weather when the car are park overnight ? will the ice cause a unbalance condition ? how long will this ice take to melt at zero temperature ?

Worst case would be a couple drops of water... if that unbalances your entire wheel you have bigger issues to deal with.

[Phil Thien]

Wait...

I thought oxygen was heavier but SMALLER than nitrogen. Nitrogen should leak more slowly.

But now two chemists are saying oxygen is larger? David Cefai and John Stankus are saying it would leak faster?

Which one is it?

[ray hampton]

Worst case would be a couple drops of water... if that unbalances your entire wheel you have bigger issues to deal with.

couple drops of water, I see tires with a cup or two of water and I am talking big cups

[Dan Hintz]

couple drops of water, I see tires with a cup or two of water and I am talking big cups

Do you understand how much water vapor is required to condense to two cups of water? Now try to get that same amount of vapor into an area the size of a tire. Good luck.