new tires on a new Prius

Personally my next wheels are going to be something along these lines:



...and a spoiler along these lines:

 

You'll be fine with the slightly larger tires, though it -may- impact mileage, but probably only a few MPGs. The Prius can afford that considering the huge increase in safety from the better and larger tires. Be aware, tires take some time to "break in". You probably won't notice anything mileage wise as you haven't driven the current tires enough to compare.

I changed Pearl's stock Goodyear Integrities to Nokian WRs after 4 months (basically "threw away" the Goodyears - left them at the tire shop). The difference in handling was like night and day, and I saw no decrease in mileage, and perhaps actually got an increase. We'll see once it warms up a bit more.

 

Hi Peterl1945, welcome to PriusChat! :welcome:

The Bridgestone web site says the tire you want does come in 185/65R15 and has 854 revolutions per mile. The stock Goodyear Integrity tires are 855 rpm, so a close match. The 195/65R15 is 833 rpm, so your speedometer, odometer, and MPG will be off. When your speedo says 60 mph, you will actually be going 61.5 mph.

 

Do it. I bought new tires in 195/60 and lost maybe 1-2 mpg. The difference in the ride and handling was simply amazing. You will love the difference. Do it.

My $.02

 

Then Bill, does this mean I *have* to get my new tires in 185/65R15 and not bigger or everything will be off?

Im not sure what I want, but Michelin, Nokian, and a few others look good to me now even after only 2 months and 3000miles !

 

I think that if you went with the wider tires you have to go with 195/60 r15

 

Peter,

As others have suggested, if you want wider thread tires, you should probably go with 195/60/15's because there will be less speedometer/odometer error than using 195/65/15's.

-- 195/65/15's will result in an under-read of 2.1%. This means that when your speedometer shows 60 mph, you are actually going 61 mph.

-- 195/60/15's will result in an over-read of only 1%. This means that when your speedometer shows 60 mph, you are actually going 59.4 mph.

For more details on what changing tire sizes will do, you can use a tire size calculator. The Miata Tire Size Calculator is probably the most popular one -- it's easy to use and read:

Tire size calculator

 

Like Tom said, but with one addition. The Miata tire size calculator, and most other tire calculators, use a formula to figure circumference and revs per mile. The numbers are off. It says a 185/65R15 (the Goodyear Integrity OEM tire size) is 824.0 rpm. Goodyear says the tire is 855 rpm. So once you choose a tire you think you'd like, go to the manufacturer's web site and look up the tire's specs. That way you won't buy a new tire that's way off the rpm the car was designed for based on a calculation.

 

I replaced the Integrity 185/65R15 with RE960 205/60R15 tires. Similar circumference, so negligeable speedometer error. Took a minor hit in gas mileage (1-2mpg) and the ride is firmer, but it drives like a different car.

 

There are 3 tires under Nokian WRS, differant speed rating, 400 and 420 which one did get, these tires are pricy.

 

Wow. 824 rpm vs 855 rpm --- that's a heck of a disparity.

I knew that tire size calculators used formulas, and different calculators use different formulas. But I never knew that the disparity between what a tire calculator's formula says and what the manufacturer of a particular tire says could be so great.

BTW, on Goodyear's website, I couldn't find rpm info. I had to go to TireRack.com to get that rpm info you found for the OEM Integrity.

 

A few years ago someone made this tire comparison chart in MS Excel. It is about the best ever comparison of tires for the Prius I had ever come across. Hope you can still use this valuable document.

View attachment Tires Comparison.zip

Cheers

p.s. Just unzip it and view it in MS Excel.

 

Good choice, I was thinking about going with the Pole Position's too.
They are surprisingly affordable in this size.
But why do you say that the RE960 is not available in 185/65-15?
It looks like they are to me:
Bridgestone Potenza RE960AS Pole Position

 

I just put a set of Goodyears on- very quiet and smooth.