Posted here as it also applies to cars & truck...
I recently purchased a lightly used 4x4. The dealer told me all about how they had put nitrogen in the tires. I'm really skeptical about these sorts of things. It really sounded like a lot of blather and we carried on to complete the deal. I suspect that there is a lot more of this out there than I have heard about or paid attention to. Today, I did a bit of googling on the topic and found a good article from Edmunds.com Well worth reading. Make your own decision but make it an informed decision.
In summary, they said :
" Is Nitrogen Worth It?
The air we breathe is made up of 78 percent nitrogen, 21 percent oxygen and a few other elements. To get the desired benefits for tires, nitrogen needs to be at least 93 percent pure, according to nitrogen service equipment providers quoted on Tirerack.com. So we're basically talking about adding an extra 15 percent of nitrogen and getting rid of as much oxygen as possible.
Based on cost, convenience and actual performance benefit, we don't think nitrogen is worth it. A much better use of your money would be to buy a good tire-pressure gauge and check your tires frequently. This is a good idea even if you have a tire-pressure monitoring system in your vehicle. The warning lights aren't required to come on until you have less than 25 percent of the recommended tire pressure. Having the correct tire pressure will get you many of the benefits of using nitrogen and will ensure that your tires last longer. "