Nitrogen vs. Air in Winter Tires

[cavalier35]

Hello,

I've seen some of the earlier posts about the pro's and con's of using nitrogen in your tires. However, I was wondering if there's any benefit for winter tires? I live in the NW and like to snowboard on Mt. Hood.

I'm wondering if there's any benefit to filling my winter tires with nitrogen because of the big change in elevation and temperature.

Any and all suggestions welcomed.

[Dr. Dyno]

I wish it was available around here. I'd have it in everything. Much less pressure rise in summer & drop in winter.
Today's job is removing the pressure sensors off my truck & dyno trailer to keep them from alarming all winter.
I should just go buy a nitrogen tank & the fill regulator and use it on all 26 of my tires.

[cavalier35]

Originally Posted by Dr. Dyno

I wish it was available around here. I'd have it in everything. Much less pressure rise in summer & drop in winter.
Today's job is removing the pressure sensors off my truck & dyno trailer to keep them from alarming all winter.
I should just go buy a nitrogen tank & the fill regulator and use it on all 26 of my tires.

haha...my winter tires don't have pressure sensors in them, so I have to look at the warning light as soon as I switch to my winter tires.

[Blogson]

Since the earth's atmosphere is about 80% nitrogen anyway it doesn't seem logical that there would be an enormous and cost effective benefit from inflating tires with 100% nitrogen. ???

[djb383]

.......and unless u pull a vacuum on the tires, how do u get 100% nitrogen back in there. 80% works for me as well.

[WJBertrand]

Originally Posted by Blogson

Since the earth's atmosphere is about 80% nitrogen anyway it doesn't seem logical that there would be an enormous and cost effective benefit from inflating tires with 100% nitrogen. ???

Bingo! The main advantage of nitrogen is that the process of separating and compressing it makes it really dry, almost no moisture at all. The only other minor advantage is that the permeability of nitrogen through rubber is slightly less than for oxygen. This means the tires should not loose pressure as quickly, the difference is very small

There's a misconception our there that nitrogen doesn't expand as much as air with temperature increase. This is not true because all gasses follow the ideal gas law Ideal gas law - Wikipedia, the free encyclopedia. This law is not sensitive to the chemical nature of the gas, so there would be no difference between air and nitrogen, besides as previously pointed out, air is already 79-80% nitrogen anyway. The other misconception that you tires will run cooler is also not true. Inflated properly there is no difference between air and nitrogen. Theoretically if one did not check their tire pressures for 6mo or more the air filled tires might loose marginally more pressure and therefore run a bit warmer due to the extra rolling resistance and tire flexure. This is a side effect rather than a direct property of using nitrogen though


What causes larger pressure changes with air filled tires is the presence of moisture. Water can change phase from liquid to gas and back, the gas or vapor phase of water occupies a lot more space than the liquid phase, hence when you convert more of it from liquid to gas with heat, you get a pressure increase greater than it ideal gas law predicts. perfectly dry air would perform exactly the same as dry nitrogen in this respect.

I guess for winter driving a good dry fill is not a bad idea. I've seen poorly maintained air compressors that spray a fog of moisture when the filler trigger is pulled. That much water in your tires might be enough to puddle, freeze and throw your tires out of balance!

[cavalier35]

Originally Posted by djb383

.......and unless u pull a vacuum on the tires, how do u get 100% nitrogen back in there. 80% works for me as well.

That's the exact same thing I was thinking, but then read they do purge the tire of any air. I'm leaning towards not adding nitrogen, unless I get access to it for free. I just don't think the value is there.

[Dr. Dyno]

Originally Posted by WJBertrand

Bingo! The main advantage of nitrogen is that the process of separating and compressing it makes it really dry, almost no moisture at all.

Very true, and it must be working. The nitrogen is guaranteed dry. Air could be all over the place. The sensors I use on the truck & trailer (now removed for the winter) alarm on both high & low pressure. I like to run the tires as close to max as possible for to reduce rolling resistance, 80 psi on the truck.
Before I got the monitor I had two tires explode. May have been from too much buildup but I don't know. With the nitrogen I get roughly half the buildup say 5-8 psi as I do with apparently moist air.

So the best source for air would be at a shop with an air tool water separator on their compressor.

[Rickl]

I'm not convinced there is big benefit to using nitrogen, but even it it were marginally superior to "air", I would still not use it because of the inconvenience.

Let's say you pay a few dollars extra to inflate your tires with nitrogen when you purchase them. A few months later when winter comes you notice the tires getting a little low in pressure. What do you do?. I'm certainly not going back to the tire shop when I have my own compressor. That would cost me both time and money. As soon as I add my own air, the initial expense for nitrogen is wasted.

As long as I am checking my tire pressure weekly , it only takes a minute to correct the pressure in my own driveway at zero cost.

[cavalier35]

Thanks for all the help and replies. The tires ran smooth all winter last year, so I'll keep them as is. Thanks