AH-Ha!


ooooh.

This made me laugh.

I too was wondering why the dealer made a big deal of telling me that they filled the tires with Nitrogen when i picked up my new-to-me 2008 4.8 X5 (just two weeks ago), but had forgotten to look it up.

Google it and you will yield a ton of information--most skeptics have never tried it they just claim it doesn't work without even using it. I can say that I can tell a ride difference and so far a slight fuel economy increase.

Does everyone know that the nitrogen fill at tire shops is about 94% Nitrogen? The generators CANNOT deliver pure nitrogen. It is also not particularly dry.

It is important to keep this fact front and center as you evaluate all the claims made about nitrogen fill- virtually all the arguments use 99.99% pure nitrogen (ie "technical pure') and certified dry as the comparator...once you acknowledge the tire store fill is marginally better than air, and no more dry that their compressed air, the whole thing falls apart.

Tire stores and their equipment vendors have spend big money on how to get an extra $30 in profit along with each set of tires they sell. Indeed, most store employees have bought into it as well.

I see green valve stem caps and just smile.

Costco Tire Center has nitrogen for free. You can go anytime to top it off.

I think nitrogen used in tire fills can be drier than an air compressor at a garage, but it depends on whether or not the garage air compressor is being maintained properly.

I think it would be a lot more honest if tire stores sold "dry fills" of whatever blend of air or nitrogen they wanted to use, as opposed to claiming that their 93% is pure nitrogen. Of course, that is what they should be providing in any case.

When I see green valve stem caps I sometimes smile, but other times I just laugh out loud.

I am aware of the information on the web, both pro and con. According to the internet, Elvis is still alive as well. It must be true. Colour me skeptical.

I am sure you can tell a ride difference, if you say so. That would be due to having a different pressure in your tires than before the plain old air (80% nitrogen) was changed out for $30 worth of 93% nitrogen.

I always check my tire pressure so it wasn't like they were under-inflated before. And y'all are acting like it was $300 to do it--it's $30 bucks--big deal. And as I mentioned it does ride a little better and so far slight uptick in MPG. Besides, I do think Elvis is alive ;).

The only gain I think is real, is the Nitrogen does not expand or contract under hot and cold conditions... thus keeping your tire pressure the same under either condition... but that is a tiny gain for $30, IMO.

I've been using it for about 2 years in my stock 235/65/17s and think it contributes to a much firmer ride (I like that) and the pressure doesn't deviate as quickly. My local tire place offers 99.9% for free with new tire purchases.

That is ABSOLUTELY FALSE.

It has been repeated and believed like an internet rumor, but is just false.

Nitrogen, like air, obeys the ideal gas law. It cannot escape this reality:

PV=nRT


End of story. But the back story:

Uncontrolled fill in tires includes moisture. Although atmospheric gases follow the ideal gas law, MOISTURE does not and will create pressure variations as it heats.

When race cars, aircraft tires are filled with 99.99% pure technical nitrogen, care is taken to eliminate any moisture. Great.

Unfortunately this "moisture free' condition is not assured with commercial 94% pure nitrogen generators. They take a truth (race cars abd jets use 99.9% pure, moisture free nitrogen) and use just the nitrogen part (94% with limited moisture control) to convince people ALL the benefits will be included.

Even sillier are the claims of safety, tire life, never needing to check air pressure, etc...