View my fuel log 2014 Mirage ES 1.2 manual: 44.4 mpg (US) ... 18.9 km/L ... 5.3 L/100 km ... 53.3 mpg (Imp)
I thought the nitrogen fill was to preserve alloy rims from internal corrosion. Seems like all the cars my friends have bought with alloys the rims always leak. My mom has used N2 in her Equinox alloys and they still don't leak. While in my limited perspective steel rims never start leaking with air and age the same way. I wouldn't pay for nitrogen but I'm also happy with steel.
Here is a good article on Nitrogen inflation. Summary: If it's free...go for it.
As an update, with my wheel (Maxxim Maze) and tire (185/55r15 Ecopia @ 45psi) combo, my average fuel economy today came out to be somewhere in the mid-thirties today. It was a lot of town driving, though. I will see what it ends up looking like when I take a drive up to the dealership over the weekend, as that will be mostly highway. I think I ended up averaging in the mid-forties last time. I just enabled cruise control, as well, so that should help.
Will be interesting to see the results.
Also keep in mind... Nothing has less rolling resistance than a set of worn out low rolling resistance tires. So if you went from worn out Enasaves to brand new Ecopias, it's possible you would not see a change (or possibly a slight decline) in your fuel mileage.
I'm running on very worn Ecopias at the moment (and getting my best fuel economy numbers ever). When my new tires go on within the next month, I expect to take a little bit of an economy hit.
View my fuel log 2013 Space Star Cleartec Intense 1.0 manual: 55.0 mpg (US) ... 23.4 km/L ... 4.3 L/100 km ... 66.0 mpg (Imp)