I boosted the tire pressure to 50 psi on the 17" tires on our 2010 Prius and doing so appears to have increased the fuel mileage. It's too early to accurately state the gain in fuel miles. Roughness and noise aren't a problem and most of the roads where we live in Florida and quite smooth. I am curious about what those with 17 inch wheels are running for tire pressure.
With the 17's on, I have set the fronts to 38 PSI and the rears to 37 PSI. Been getting near 50 MPG mostly highway driving.
Don't know why I didn't notice this thread. Anyway, our 2010 Touring came with 17" Michelin Pilot HXM4 215/45R17. I'm just now phasing them out, for Primacy HXM4. I tried low 40's psi at first, when we first got the car, but quickly realized that these low profile's are PUNISHING at higher pressures. Beside the harsh ride, I suspect it's also going to accelerate wear of bearings and suspension. Accordingly, the most I'll set them to is 36 psi (all four), and I'll let them drop below 34 below making any further adjustment. FWIW the the decal in door jamb says 35/33 (front/rear) for the 15's, and 33/32 for 17's.
No, just the warmer months. For the winter months, run on snows mounted on 15s steel rims. Fronts set to 37 PSI, backs 35 PSI. Getting mid 40 MPGs.
I set our 15" X-ice at 40 (all around), but just, no higher. And the ride is getting a wee bit firm, not as bad as the 17's though, lol. And through winter if they drop a bit from 40, that's fine.
I run 38 psi front and back, as for fuel mileage, see below. I tried 42 psi before, but was starting to get a wandering on-center feel on the freeway speed. I don't mind the stiffer ride of running higher tire pressure though.
Warmer Bay Area months I get 50-53 mpg, and for the few months of cool and rainy weather, I would get 47-50 mpg. Tires are the stock Corolla S Firestone FR740, non-LRR tires I think.
