Yes I have tried N, for over two years, but the differences were so small that I couldnt notice them,
There is no way in hell that you can benefit the same advantages with a road car as a race driver or an airplane or even the NASA Space Shuttle.
The only thing left is the fact that N filled tires doesnt leak as much, but as already mentioned before, the difference is so puny it is ridiculous.

You go on ahead and spend money on your bogus gas, I like many others will happily stick with free and available air.

Summary:
Though the study was not specifically designed around evaluating the effects of nitrogen inflation, a sufficient number of tires with different inflation gases were tested in the various test programs to yield a number of statistically significant results. NHTSA testing of tires has confirmed that using nitrogen as an inflation gas in place of air slows the static IPL of the tire significantly. In the 90-day static room temperature test, the inflation pressure loss rate for tires inflated with nitrogen was approximately two-thirds of the loss rate of tires inflated with air. Dynamic testing on a roadwheel test shows the differences between the diffusion rate of air versus nitrogen versus 50/50 N2/O2 are maintained at higher temperatures and dynamic conditions (i.e., simulating rolling operation on a vehicle). The decrease in permeability for nitrogen gas was observed to be independent of tire innerliner composition and thickness, thus applicable to all tire types studied.


Inflating with nitrogen in place of air had little or no direct effect on tire rolling resistance performance. It should be noted that inflation with nitrogen merely slows the rate of diffusion of gas from the tire and is not a substitute for regularly maintaining tire pressure. Limited static inflation
pressure loss rate testing with a 50/50 blend of nitrogen/oxygen inflation gas produced mixed results. The IPL for all tires began significantly higher, but dropped by the end of the 90day test period to approximately the loss rate of air, which contains only 21 percent oxygen. Analysis of the gas content at the end of the test period confirmed that the rate of oxygen loss from the tire was approximately four times the rate of nitrogen loss averaged over the 90-day period. The reasons for the drop in IPL over time for the high-oxygen-content tires are unknown.


Seventy-six tires from 19 vehicles were measured for tire pressure and oxygen concentration. For the forty tires with the DOT code recorded, the average age of the tires at the time of inspection was 2.8 years with tires ranging for 0.6 to 6.8 years old. The average inflation pressure of the tires was 29.1 psi. The average percentage of oxygen measured in the inflation gas of field tires (on-vehicle tires) was 15.0 percent, and most values were significantly less than the original air inflation level of 20.9 percent. This suggests that the partial pressure of oxygen in the tire decreased
significantly during service. Probably there are two contributing factors: first, oxygen has a higher permeation rate than nitrogen, and second, oxygen is consumed.


Using the estimate of 0.041 percent/month for each percentage reduction in O2 percentage and the average IPL loss of 2.13 percent/month for the tires studied in the lab, the calculated IPL of these field tires would be reduced by approximately 11 percent (0.24%/month) due to the change in inflation gas composition. In other words, if a normally maintained in-service tire is not punctured or deflated, the faster diffusion/consumption of oxygen relative to the nitrogen content of the inflation gas results in an increase in the percentage of nitrogen gas from the original 78 percent to as high as the 91 percent observed, thus lowering the effective rate of inflation pressure loss. This means that the average loss rate for tires in the field may be considerably different than that measured using freshly inflated new tires. The benefits of nitrogen inflation on pressure retention of tires in service may be overstated by testing with new, freshly inflated tires in a laboratory test. Based on this study, the mean advantage in IPL for tires in service will be approximately
25 percent.


The results for 23 tires subjected to hundreds of hours of laboratory roadwheel aging with air, 50/50 N2/O2, or nitrogen inflation were inconclusive. Results did not indicate a correlation between the inflation gas used and the time to failure in this particular roadwheel durability test.


The results for 44 tires subjected to oven aging for 5-weeks at 65° C, followed by the 35.5 hour FMVSS No. 139 Endurance and Low Pressure test sequence, showed the oven and roadwheel test conditions to be sufficiently severe to differentiate between 50/50 N2/O2 inflation and the other two inflation gases, air and nitrogen. However, the oven and roadwheel test conditions were not severe enough to differentiate between air and nitrogen inflation. The oxygen concentration
measurement data from both the accelerated dynamic roadwheel aging and static oven aging also showed a much more rapid diffusion/reaction of the oxygen portion of the inflation gas when compared to the nitrogen gas.


An analysis of common inter-belt rubber material properties from tires retrieved after an average of four years of on-vehicle service in Phoenix, Arizona demonstrated that a portion of the oxygen permeating through the tire is absorbed and reacts with the internal tire rubber compounds, which eventually leads to degradation of inter-belt adhesion. Accelerated laboratory aging of the tires using a two-hour roadwheel break-in and five weeks of oven aging at 65° C with an oxygen-enriched inflation gas yielded changes in the level of absorbed oxygen, tensile properties and peel strength properties in the internal belt package rubber that were similar to 4-year-old tires retrieved from service. Hence, out of 11 tire models that successfully passed the FMVSS No. 139 Endurance and Low Pressure tests when new, 3 models failed when oven aged prior to the road-wheel test. These changes in material properties and roadwheel performance could be replicated in the laboratory through the use of elevated temperatures and oxygen-enriched inflation gas despite only running the tires 100 miles at 50 mph on the roadwheel during the break-in. Therefore the results strongly indicate that the degradative reaction of the internal tire rubber components is a product of the internal pressurized oxygen and temperature conditions rather than from purely mechanical fatigue of the tire structure. Thus lowering the percentage of oxygen in the inflation gas may be one way to lessen the availability of oxygen to react with and degrade the internal components of the tire.


A primary positive result expected from nitrogen inflation may to produce more uniformly maintained tire pressure over time, which would help maintain tire performance properties such as handling, rolling resistance and durability. As seen from the effect of liner composition on IPL, this may be more important for some tire models. Also, there is a strong scientific basis for concluding that reducing the oxygen content of the inflation gas will reduce the internal thermooxidative degradation of the tire, which may aid in retention of durability.