Mileage declining at 23,000 miles

Not that tire, but I did a tire replacement earlier this spring, with Green-X rated Michelins, and am just now starting to crawl back out of the mpg basement. The new tires are excellent otherwise, but I did take a bit of a hit. A few months later I'm getting optimistic that they are breaking in, and the mpg is coming back.

I have had tire replacement where I didn't skip a beat, but I guess what I'm saying is: it can be the new tires, regardless of their rolling resistance ratings, and then it just takes some patience.

I hope...

 

Did they put the correct 0W20 oil in, some have reported a hit in mpg if the dealer uses 5W30 (or thicker) instead.

 

I don't think that either oil or new tires will account for a 20% mpg drop.

 

A lead foot on the accelerator might though

 

If you have a trickle charger you can try charging the 12v once or twice a week. Otherwise try 40 psi front and 38 rear on the new tires. Just a little higher then what you have.

Posted via the PriusChat mobile app.

 

I put ours on a smart charger pretty much every day there's likely to be no use of the car, and just leave it on till next usage. A quick-connect makes it more convenient. Appreciate this doesn't work well for people street parking or condos.

 

I put Continentals on all our cars ... all the 16's have them now ... all Four Touring Models. Typically we take a hit from the older hard tired to the new soft with lots of tread .. it's normal.
Make sure the Continentals are properly filled .. we run them in the 33 range. They have softer side walls vs some other brands.

My favorite All Season tire brand .. have them on the SUV's -- Hybrids ... Euro's ... love them.

 

Any new tire will reduce efficiency; even if it's a low rolling resistance tire, it still has higher rolling resistance than the worn tires you replaced. Rolling resistance decreases as tires age and as their tread is worn away.

I have the same tires, going on 35,000 miles on them.

Edited to add: At the 2018 Green Grand Prix my car returned 62.8 mpg; at the same competition, on the same track, at the same time of day in 2019 it only got 59.2 mpg. Was something wrong with it? Of course not: in 2018, the weather was overcast but not raining with temperatures in the mid-60s, while in 2019 it was 32 degrees and sleeting; even in a closed competition like that, the traffic of 40+ other cars was different each year, in many unpredictable ways; I had a (200+ lb) passenger in 2018 and none in 2019; etc. Even if you think everything is the "same" it never is; there are way too many variables in daily driving. The question is, are those variables enough to explain the drop in one tank's mileage? They certainly could be. I would give it two more tanks, and if they are as low, then you can be reasonably certain there's a problem with the car itself (or the way you are driving it) and it isn't just a product of the natural variability in traffic, weather, wind, route, trip lengths, and so on. My 2 cents.