No subject

was no side-by-side comparative study for trucks either, some trucking
company have reported up to a 48% increase in thread life but, more
important, the possibility to recap the tire up to 5 times instead of 2-3
times, after they switched from air to nitrogen. So, on truck tires with a
250-300Kmiles thread life which are recaped to last over a million miles, it
does make a difference. Does it on the 30-50Kmiles high performance tires we
use? Still to be proven. Beside, are you recaping your high performance
tires. I suppose you don't.

Nitrogen gives a better gas mileage: FALSE
This is a deduction from the fact that nitrogen leaks less but I found no
comparative study. The deduction come from the fact that Nitrogen leaks less
than air, which is somewhat true. As said earlier, over a year, a nitrogen
filled tire will loose 2.2 psi only when a air filled tire will loose
2.7psi (average of 20 tire brands tested). I don't think a
0.5 psi difference over a year will make a difference, especially if you
check your tire pressure every month. Beside, the choice of tire will vary
this pressure drop from 1.0 psi to 7.8 psi, so the choice of your tire is
much more important than Nitrogen. Do you consider the air permeability of
the rubber when you choose your performance tires? I think not. So if you
don't care about a 800% difference in pressure drop, why should you care
about a 20% difference?

Of course, this is just what I found. YMMV. Someone on another list has even
reported a 3MPG difference when switching from air to Nitrogen (but he
forgot that he was switching from worn out tires with unknown pressure to
brand new tires with on-spec pressure at the same time ;-)



Vincent