New tires and bad MPG's?

A new tire is a larger tire, so it will show less mileage. A new tire is also a tire with lots of tread, so it will have more nonlinear movement.

Not all sizes are LRR Firestone Affinity Touring

the service light comes on 500 miles before the next service is due.

 

Low Rolling Resistance is a buzzword for a tire that gets good gas mileage, as shown in the link, H rated 195s are LRR, but S rated 195s are not.

 

Not sure if you get a lot of snow where you are, so I don't know if I should recommend these or not. I recently bought a set of Michelin Energy Saver A/S for our Prius. Same size as yours. I have noted that the MPG has actually improved quite a bit from the original "Integrity's". Also the Energy Savers are LRR type tires. It does seem that after a short break in period that the mileage has also improved.

A lot of folks report drops of MPG, then afterwards the MPG returns. Some say the tire needs to be broken in. Others will say it has to do with the circumference of the tire being larger which throws the numbers off. It does seem that there is normally a slight drop in MPG then after time the MPG improves. With the change we made, the MPG stayed pretty much the same and then increased as the tires broke in. I base this due to the fuelly stats and detailed records that I have maintained on the Prius and MPG.

I have heard that the Energy Saver A/S does not do well in snow, so that is the hesitancy I am talking about.

If you can return the tires, you might consider a set of the Michelin's if they fit your budget. They are a little pricey, but in my opinion I think you will find them to be a considerable improvement.

Look at my signature file. I have two fuelly listed there. One is the lifetime MPG and the other one is just for the Michelin's.

You might also consider the Bridgestone Ecopia 422. They too are also LRR tires.

Concerning the air pressure. I would recommend you run no more than the maximum pressure marked on the sidewall for the front tires, and run the rear tires two pounds less. That should help with the MPG. If you find the ride is too harsh, try dropping the pressure a couple of pounds and go from there.

Best of luck to you and "Welcome" to Prius Chat.

 

Tjamscad - Oops... the classic tire "Gotcha." TirePlus sold you the "S-Version," which is the 89S SL, and is the non-LRR (Low Rolling Resistance) version. If you had purchased the 89H SL LRR Fuel Fighter version you would not have experienced such a big "Hit" to your MPG.

 

And note that some of the drop is just an illusion. The computer thinks your tires are always the same size, so they appear to get worse mileage with lots of tread and the appear to get better mileage when they have no tread, even if this is not a 'real' effect.

 

A LRR tire would have helped, but even with what you have, some of your MPG may return with use, as tires roll easier as they "break in".

I replaced the original Yokohama LRR tires on my 10 Prius with Goodyear Fuelmax LRR tires. We saw an immediate 4 mpg drop. I was happy to take the MPG hit because the Fuelmax tires have so much less road noise and better ride than the Yokohama tires. Now after 15,000 miles, the fuel Max tires have less wear than the Yokohoma's, and MPG is back nearly to the original numbers. I run the goodyear tires at 44psi(sidewall says 45 psi max), which seems to be a good compromize between ride and fuel economy.
The Yokohama's were worn out at 30,000 miles, while the Goodyear's look like they should make atleast 50,000.

 

Well if it's too late to exchange your tires for LRR tires you should at least put 42psi in the fronts and 40 psi in the rears that should help you a little bit.