I was wondering if having 17 inch wheels will decrease MPG? I didn't test drive the car and just bought it and noticed that the ride is so much louder than the 15 inch wheels. Is that normal or just that the tires are new? Any recommendations on waxes, clear bras, or some clear coat protection for the pain?
Yes, you do take a hit going to larger rims (and tires). Anytime you add to your unsprung weight, it takes more power to spin 'em. It not a big mpg hit though. Louder? That's not relating to rim size, but rather tire chemestry, and tire pressure.
Take a look in the 2010 Prius forums, there is a subforum for recommendations on products for taking care of your Prius. In regards to the tires, expect a 2 -3 mpg drop compared to the 15" tires. But you have those nifty LED headlights, quick ratio steering and other fun things to put that smile right back on your face.
