By now, most everybody is aware that Consumer Reports went to press with some test information about nitrogen tire inflation (http://blogs.consumerreports.org/cars/2007/10/tires-nitrogen-.html). They filled 31 tires with air and 31 matching tires with Nitrogen, let them sit unused, and measured the pressure loss 1 year later. They found that the average air filled tire was 3.5 psi (11.7%) below the initial 30 psig inflation pressure, while the average nitrogen filled tires was 2.2 psi (7.3%) below the initial inflation pressure. While this was in no way a scientific test, nitrogen inflated tires clearly retained pressure longer.
I was extremely disappointed that a reportedly unbiased organization like Consumer Reports did not perform a rolling test comparing results between air and nitrogen. There have been numerous over the road tests conducted, most of which showed significant improvement in fuel economy and tire life. A problem with a large portion of the existing data is that arguments could be made that they weren't unbiased (i.e. inflation equipment donated, equipment manufacturer reporting results, etc.), and it is in this area that Consumer Reports could have really provided a service to the American public.
Get Nitrogen has been preparing a formal response, and I expect that to be submitted this week. I should have a copy of their response to Consumer Reports once it is submitted.
