NewTires, differnt size?

Not a problem and as a matter of fact i'll be putting 195/60/15 next.

195mm wide / 117mm thick (195 x 0.60) / 15" diamater

205/60/15 wouldn't be a bad either either, but it might slightly hurt mpg while increasing grip. I'm not sure if they even fit on the Prius rim though.

 

Ask them to tell you what the revolutions per mile of the different sizes are in the type of tire you are interested in. The Goodyear Integrity 185/65-15 is 855 rev/mi. In some types of tire the 205/60-15 comes closer, usually the 195/60 is a little smaller in circumference (i.e. more rev/mi) and the 205/60 is a little larger than the stock 185/65. The 205 would put a little more tire on the road, 2 cm wider than stock, so it would handle and stop a little bit better but most likely not enough to be noticeable.

Information such as rev/mi are available for a lot of tires at tirerack.com just click on specs for the tire you want.

EDIT: I just noticed your from Oregon, go to Les Schwab and take a look at the Toyo Proxis TPT. They come in all 3 sizes (185/65, 195/60, and 205/60). I think I am going to use them in size 205/60-15, there should be absolutely no problem with clearance with that size.

 

What is working to improve traction in snow? On a moderate uphill grade in a small amount of wet snow, the car was helpless. Very different from other compact front-wheel drive cars I have had.
Is anyone using studded snow tires?
Robbid - Portland, Maine

 

Nokian's have a great reputation. Just went to their web site, looks to me like you made a good choice. Let us know how they work out on ice and snow etc.