Any thoughts on using nitrogen in the tires on my Turbo S?

 

Excellent discussion here:

https://www.6speedonline.com/forums/...gen-tires.html

 

Had nitrogen in my tires for 2 years before recently replacing the wheels and tires. I was very pleased at the consistency. Mine is a weekend toy and in some cases is not driven for weeks at a time due to travel/work, etc...I didn't want to bother with having to address tire pressure when I take it out so I had it filled with nitrogen.

Only reason I don't have it in currently is becuase the facility that installed the wheels/tires didn't offer it. I've read through threads like this where each goes back and forth about the benifits, how it's a complete waste of money, etc...facts are, cost aside, if there are any, is that nitrogen inflation does offer benifits.

 

When the tire is mounted on the rim, before any pressure is applied, it has 78% nitrogen in it from the free air. To obtain 100% nitrogen this air must be removed. I am not sure how the mounted tire can be evacuated and not collapse the tire from the negative pressure.

The main value with nitrogen is the ( possible ) moisture free gas. It is thought that the moisture will expand when heated and raise the preesure. But the layten heat off vaporization requires 212F and 783 BTU/# at 1 atmosphere. The 212F goes up with the added normal pressure ( 30 PSI ). Many standard air compressors have water separators and dryers. So normal air could be just as good if any drying treatment is used. Even if it isnt, the chances of converting what little moisture to steam is slim.

All gases react the same way with the change in temperature. Heat them and they expand.

 

Great explanation Kanjisan

 

Heat capacity of air (40.85% rh) is nearly identical to pure nitrogen. So the idea that H2O somehow contributes to pressure variances based on thermal input is hogwash imho.

 

To paraphrase Ghostbusters, "Back off, I'm a chemical engineer". Trust me, there is absolutely no performance advantage in using nitrogen versus air for tire inflation, as long as the air is dried. And it is a subject for debate that the remaining moisture after compression makes any difference. Nitrogen is less permeable through rubber compared to oxygen, but since air is already 79% nitrogen, it's not worth considering as far as retaining pressure goes. Maybe a slight improvement on maintaining tire pressure, but big deal. Nitrogen inflation is a scam. Check out the link above provided by bbywu if you want to get into the physics of it all.

 

Forget all the chemistry and look at the physics. How do you remove the "air " that is in the tire after mounting it. Any attempt to suck out the air will colapse the tire ( the bead design isnt able to deal with negative pressure ). Also, the nytrogen molecule is a hexagonal crystal structure ( non-compressed ) the same as carbon ( in the tires ) and I doubt that there is an open path to get out.

If you are still interested, I will sell you some 79% nitrogen at a discount.

 

You don't really "suck out" the air. You fill and purge multiple times so you never get out 100% of the air but most of it. In tires, nitrogen is a gas and has a linear geometry. Only at extremely low temps can you solidify it.