Im new to the Prius world so please bear with me. Ive also used the search and cant find a direct answer to my question. So... Im driving a 2010 "V" with 215/45-17 tires and rims the Prius models that run the 15" tires and rims use 195/65-15 tires and from what ive read the 15" tires and rims tend to get better mileage. In my search I see the 15" diameters are avg 25" while the 17" diameters are an avg of 24.7" . I understand there is also the difference of tread width creating contact and drag but would "plus" sizing to a 225/45-17 tire with a avg diameter of 25 help improve mileage over the smaller 17" diameter tires? Lastly do the LRR tires really get much better mileage or can milage be improved with a "summer" or performance tire by using max air pressure?