Question: What is with all of the hype about filling your tires with nitrogen? How can all of the bold claims that are advertised be true? Considering the fact that the air that we breathe (and we run through our compressors) is about 80 percent N2, where are all of the benefits coming from? The only difference that I can think of would be the possibility of getting very wet air from some sources.
Another similar question would be from the use of CO2, as from a popular trail accessory such as a Power Tank. This gas is much heavier than air or nitrogen. Could that cause any negative effects from its use?
Answer: That is a great question, and while I have been using CO2 for some time now and have even written a "Willie's Workbench" on the subject (June '06), about the only thing that I know about N2 is that a lot of race cars use it. I gave Steve Sasaki of Power Tank (www.power tank.com) a shout for help. He got back to me with some interesting information. It seems he was in the process of doing some testing on the very subject and was nice enough to share some of his information with me. He said that when he was finished with his testing, the completed information will be on his company's Web site. But for now, here is what he had done.
He took three equally sized bottles and filled them with N2, CO2, and air at 40 percent humidity and subjected each one to four different stages of temperature changes with interesting results. OK, his tests were more on the practical side than what a true scientific lab would use, but for our purposes, I would say they offered a reasonable amount of accuracy.
|Surface Temperature ||N2 ||CO2 ||Air *|
|-11 F (freezer) ||40 ||40 ||40|
|86 F (office) ||52 ||53 ||53|
|105 F (sun) 55 ||55 ||56|
|117 F (direct sun) ||56 ||56 ||57|
|*Air at 40% humidity|
Steve's conclusions so far are: "Low Pressure Expansion Test: So what kind of pressure differences would we see in passenger-car and light-truck tire pressures over a 128-degree temperature swing? The results show nearly identical thermal expansion rates for the three different bottles, showing that N2 as a tire-inflation gas is not appreciatively more stable than CO2 or air within the pressures relevant to automotive tires. We saw a 1 psi pressure change for every 8-degree temperature change."
You did bring up a good point as to moisture content of air. The CO2 and N2 contain no moisture. If you were constantly refilling your tires in an area of very high humidity with air, then in theory you could collect a considerable amount of water in the tire that could cause balance problems and rim corrosion.
This would be just one of the advantages of CO2 or N2 over natural air. It's also my understanding that the molecules that make up both CO2 and N2 are larger than O2 molecules. Tires will lose air over time, due to the fact that they are not a perfectly sealed envelope due to the porosity of the rubber. With CO2 or N2, the loss would be less over a given time period. How much less remains to be seen.
Question: I have an '85 4Runner, with the 22RE engine and automatic transmission. I just recently put a Wagoneer Dana 44 in the front, and I plan on running 37-inch tires. I ran 35s on the Toyota axle for more than a year, but I want lower gearing with the 37s. Do you know the name of the company that sells the adapter for the automatic to run the manual transfer case? I would like to go with dual cases with my automatic
Answer: It's not a real popular swap, plus it's a lot of work-but I guess if you're stuck with the auto shifter and don't want to swap over to a standard trans, you don't have much choice. There is a company called Inchworm Rock Walking Gear (925/766-6555, www.inchwormgear.com) that does indeed have the adapter you're looking for. It took a bit of engineering to develop it so the price reflects that work. It allows the use of Inchworm double transfer-case adapters and geared cases behind your automatic utilizing the 23-spline input shaft, and allows stock rotation of up to 10 degrees for added ground clearance. This adapter does require a complete teardown of the factory automatic transfer case as well as some small parts-changing inside the transmission.