Well, I had another Homer moment today but in the hopes it might help someone else in the same position I thought I'd share.
We have a little over 2K worth of miles on Maximis, at a little over two months of ownership. In that time I haven't checked the tire pressure... at all.
I've put air in our Durango twice during that period of time and in my defense this new technology stuff is still confusing this old man. For some reason I thought that, just like I didn't need to worry about oil changes for quite some time, that Maximis would tell me when I needed to put air in. I could have sworn I read something like that.
Except -- in putting air today in the Durango I took a quick look at the manual for the C-Max and see that it only *warns* you when the pressure is very low. Not when you should be putting it in as usual. Doh! Okay, so I measure it and it seems *really* low to me (about 30 psi cold). The tires are all rated at 51 psi max, so I figure I had better put at least 45 in them, which I do.
Then I drive to my usual location and back, a round trip of 24 miles I make at least twice a week (so I'm *real* familiar with the mpg I should be getting). Normally I get around 45 (it's a mix of city/highway, with the emphasis on the highway) and, of course, it always starts from a cold engine both ways (before and after tennis <g>). Today I get 56 mpg.
Now -- it's a bit cooler than usual (near 80 degrees when it's been in the mid to high 80's) so perhaps the A/C (which I always have set for 73) is working less, but I also have to think that at least some of that was due to the tire pressure. If that's true, the tires have mostly been low since we've got it (because I noticed how different the ride is right away -- a bit rougher but not at all unpleasant).
I'm going to start paying closer attention to tire pressure.