Originally Posted by Meese
My on board compressor has a 90° air chuck on it. That avoids those gas station hoses and searching for quarters. Plus it's always with me, no matter where I am.
Good point. I have one exactly like it (thank you!), but I have been reserving it for emergencies only, and assumed that you did too. The clip-on 90 degree stem does the job well. I don't carry it with me around town, but always have it for longer trips.
I once read a convincing paper about air, nitrogen, and water vapor in motorcycle tires. It was well-written, with an explanation of the physics involved. I have been searching for it to share with everyone here, but no luck so far. Here is my takeaway from the article (from memory):
* Nitrogen in motorcycle tires is better than air, but not worth the extra cost. Nitrogen does not leak through tire rubber as quickly as oxygen, so a nitrogen filled tire will hold its pressure longer.
* Because oxygen leaks out of the tire at a faster rate than nitrogen, your tire will evolve to a nearly pure nitrogen content over time as you add small amounts of air. The added air is 80% nitrogen, so very few oxygen atoms get in. Why pay for nitrogen when you tire will evolve to it anyway?
* Water vapor in your tire is bad. It will cause a greater variance in tire pressure with changes in temperature. It has corrosive effects on metal parts in your wheel. (I realize that alloy wheels won't corrode, but what about the affect on the TPM?)
* Compressors with reserve tanks introduce far less water vapor into your tires compared with the mini compressors that have no reserve tanks. This is due to the physics of the reserve tank and its size compared with the air capacity of a motorcycle tire, not special moisture filters and draining. A mini compressor on a very dry day will be close to what a reserve tank compressor does even when the relative humidity is much higher.
That last bullet is why I have been using gas station compressors rather than my own very nice mini compressor, perhaps erroneously. I assume that the gas station compressors have reserve tanks built in, leading to drier air in my tires. Maybe I need to re-think my approach, especially in the summer when the air is very dry here.
Of course, one of these days I should go out and buy a decent air compressor, but I have no room to put it in my garage, even the ones that fold up.