[rdclark]

IMO you should be doing better. On road trips, mostly Interstate, our 2015 turns in 32mpg on flat terrain with CC set to 65. In daily around-town mixed driving, it averages 25.

The tires are inflated to 32, and they are aligned. We accelerate gently. We maintain steady speeds. We use Top Tier gas (87 octane). And really, that’s about it.

There’s something wrong with your car, or with your driving.

 

[rdclark]

I meant to mention: Short drives kill overall mpg. By short I mean anything under about 25 miles.

By way of illustration: I have a 30 mile drive on I95/495 around Wilmington DE that I make during the early afternoon on weekdays every couple of weeks, at 60 to 65mph. Normally I average 32mpg or a little better on this drive. But I don’t hit that number until close to the end of the drive; if I stopped after 20 miles, it might be 25mpg. After 10, maybe 18.

You get terrible economy when idling, warming up, accelerating a cold engine, etc. The higher the proportion of your driving spent doing those things, the worse your overall economy will be.

 

[rdclark]

Sending this from Australia. I am surprised that your 'top tier' gas is 87.

1) "Top Tier" in the US is a designation created by fuel marketers indicating that the gas meets certain standards for detergency. It has nothing to do with octane; all grades of gasoline can meet Top Tier standards.

2) 87 Octane is the recommended fuel for non-turbo Foresters in the US.

 

[rdclark]

I have a 2015 Forester. My mileage dropped when I was forced to buy new tires. The OEM gave better mileage. My Michelin probably are safer. Mileage dies much above 70. At 65mph it is great. At 80 it is not. It was probably rated at 65mph. Great car but not perfect. Very happy with my first car I ever bought new. I have been buying cars since 1970.

I also have a 2015 and also noticed an apparent mileage drop after installing new Michelins (the rebadged Defenders that Michelin supplies to membership clubs, labeled X-Tour AS).

Then I realized that the smoother, quieter Michelins were encouraging me to drive faster. I made a point of reproducing the kind of driving that originally produced 32mpg on highway trips, on the same roads, same speeds, same conditions, and it turned out the fuel economy was the same. Toda, a year into the new Michelins, everything is fine.

 

[rdclark]

I'm not thrilled with my mileage ... Is it safe to say the computer is pretty accurate?

You should be thrilled, if getting the best fuel economy of any car in its class is something that thrills you.

I have found my 2015 2.5 Premium trip computer is usually about 3% high compared to calculated, per tank. Because it's consistent and reliable, I find it useful.