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Local news article claimed 1-1.5 mpg improvement. Anyone here tried it ?



Total BS.

When you just fill a tire with nitrogen it's not 100 % nitrogen in it. There is still regualer air in there. Anyways the expansion of diameter of the tire while hot is mostly a fuction of the humidity of gas trapped in a tire.

I crew on a very competitive local NASCAR crew. We watch the diameter growth of tire with respect to tempurature. Just putting in nitrogen doesn't cut it. We need to PURGE the tires of all their gasses about 3-5 TIMES to get the humity down to 3-8%. We have a special tire air humidity guage to check this.

Now if the tire monkey that mounts your tires uses and bunch of soap and water to mount your tires, you have a bunch of humidity trapped in them.



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Another advantage of filling a tire with Nitrogen is that the itsmolecules are thicker and bigger than air..
So if the tire has a slow leak it takes considerably longer for the tire to deflate.......



I don't buy that. Gas molecules thick or not can get by any leak.

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If regular air expands more with heat than straight N2 then you would think that you get better mileage with regular air as the pressure builds and rolling resistance goes down.



That's a good point. I remember when honda offered the CRX HF (high efficiancy) model than had narrower tires with high recommended inflation pressures.

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From what I understand it's out of convienence. They have pressurized nitrogen readily available and don't need to have a compressor. I'm not sure what they already use the nitrogen for, maybe someone else does?



Yes it is convenient. It's about the cheapest thing out of a tank and will run a air tools. And you can turn the pressure up more than a common compressor can pump out for those tricked out ported NASCAR air guns.