New Michelin Energy Savers: Significant MPG drop

Most of that may come back after the tires get broke in.
When I replace my worn out Yokohama Avids with Goodyear Fuel max tires, I saw a 4 mpg drop. Now ith 10,000 miles on them, about 2 of those 4 mpg have come back.

 

Ocean,

Have you personally checked the pressure on the tires with a good tire pressure gage? If so, would you please post the pressure for both front and rear. Also, would you please update your profile with your location that way we have an idea of what type of topography you drive over.

FWIW, I mounted a set of those on the Prius we own. I did not note a large drop. At first I thought I saw no drop at all. However after having the tires now for a while, it seems like the mileage might have dropped about 2 MPG but has regained all of that and more. I have about 2500 miles on our set now.

Anyway, please check your pressure with a good tire gage and report back with the pressure. It would help all of us here with the additional information.

 

...were they the regular Gen2 size or the cruising model?

 

Fronts should be around 40
Rear should be around 38

If you are loading heavy with a lot of weight and or people your mileage will vary. Also new tires do take a few miles to break in.

Would you please be so kind as to update your location in your profile when you find the time.

Most here have liked the Energy Saver A/S however a couple have posted talking about drops such as yours.

It is best if the front tires have two pounds more than the rear due to the weight distribution of the car. Toyota suggests 35 F 33 R which is a minimum and provides a soft cushy ride. However most of us here have found that if you pump them up the MPG will improve.

If you don't like the tires, take them back to the dealer with the invoice and ask for another set. Michelin has a 30 day policy on that.

Sorry I can't be of greater assistance to you. Hopefully other's here will have better suggestions.

 

Please let us know where you got these tires (TireRack.com?)

>>But I am just recalling a prior thread here just a few weeks ago, there are two versions of the tire, (1) Energy Saver and (2) Energy saver A/S. It is the latter tire (A/S) that has the good MPG ratings. make sure you have the A/S if not you might want to switch. See TireRack.com for your Prius to see the A/S version available.

 

Well in that case I am out of ammo....35 MPG is strikingly low for Prius and suggests either heavy loads with short trips, or something wrong. Tire rolling resistance goes down over the first 15-min as tire heats up. Also tire pressure goes up as tire heats up. So maybe 30% improvement in first 15 mins (now I cannot remember 30% improvement in what-I think rolling resistance is 30% better and MPG delta = ~20% rolling resistance change). You already mentioned heavy loads. I have a general equation for MPG vs. load but I don't think it helps too much. Make sure you're tire size is exact per TireRack.com recommendation.

We have a survey of questions for low MPG. 12v battery is one thing, many others.

 

If 40 was the average before the switch, 35 isn't to bad for new tires

40 is really low, 15% hit for 2,000 miles is to be expected, I'd be much more worried about the poor performance before the tires.
So what are the option's, getting new tires, of which, you have the best there are, I'd start looking for the real problem and not at the symptoms.

 

if the car is loaded to the max all the time, 40mpg isn't bad.

 

The OP's history illustrates he is using his Prius with heavy loads unless he is not working out of it as originally planned. That would explain the low mileage. If you read all of his posts you will see he was wanting to haul stuff for his job.

I think he has a combination of factors that is causing the drop from what a lot of us like myself here on PC see out of our Pri. (Heavy Load, Short Trips, New Tires, etc.)

I can only go by what I have seen on the tires here on our Prius plus what other's have posted. I have found the Energy Saver A/S to be a good match with the way I drive our Prius. In fact I have found that they seem to be much better than the original Integrities.

OP's original post is below discussing the heavy loads.

Prius as a carpenter's "work truck?" | PriusChat