New tire and bad mpg

All new tires will have an intial break-in period. That's normal.

After a few thousand miles, they will wear down enough to lose that sticky quality from the tiny firm edges on all the tread surfaces. Then you'll find out what the rest of the life of the tire will yield for MPG.

The first rotation will bring back a minor MPG down too. But that wear down takes less time to overcome.
.

 

I recently put Pirelli P3s on my Prius and the mileage actually improved 3-4 MPG. My average is now 44-45MPG.

 

They still selling P3? I thought P4 is the replacement. They have the 44 PSI max.

I got a set of P4 for my wife's Prius. It gets maybe 1-2 mpg lost (new). But handling and crosswind issues I had are now gone.

 

FYI Premium gas will not only NOT increase your mileage,, but it will decrease it!

There is actually fewer BTUs available in a gallon of higher Octane gasoline than a lower octane.

Icarus

 

Also note tire diameter when replacing tires. Different tires, even of the same size, will have differing circumferences, which introduces error in mileage measurements. You may think you are getting better mileage, or worse mileage, but it may be an illusion.

Tom

 

I put Pirelli p4 four season plus tires on my wife's 05 and her mileage dropped from 45 to 38 mpg. Had Bridgestone Ecopia on there. Not impressed with the Pirelli.

 

I just have put on new Bridgestone Ecopia 185/65R15 tires on my '04 Prius. Original equipment size. I had 195/60R15 's on it before.

Mileage slightly better. The noise level is unbelievably LOW! The ride is smooth even with 44 PSI in front.

I Love 'im

 

EP422 Plus I assume?

 

I've been really happy with my old Ecopia EP100s. I'm on my second set now and although their longevity is nothing spectacular (though still quite ok at about 75000km / 45000 miles), their proven low rolling resistance performance makes them a winner for me. I've been consistently getting tank averages in the 52 to 58 mpg range for the past 3 or 4 years with these guys.