Just took delivery of my new 2012 Prius II yesterday. Is there much benefit to increasing the tire pressure beyond what they do at the dealer?
Toyota's recommended pressure gives the best ride. You may find improved handling, Fuel Economy, braking and tire life at a higher pressure. This will vary by tire model. My OEM Goodyear Integrities worn out on the outside edges even at 42f/40r PSI. My Goodyear Viva Authority Fuel Maxxes wore out in the center, at 38f/36r PSI. All you can do is watch the tire for wear issues. Even wear should yield the best handling, braking and tire life. Under no circumstance do I advise driving with pressures above the max pressure listed on the tire itself.
For starters, what pressure tire did your dealer provide? Don't assume they obeyed the door placard, check for yourself. New car owners here have reported a wide range, from a few barely over 30 psi (apparently for a softer ride during test drives) to many at 40 (the pressure for the boat ride across the Pacific, which is supposed to be reduced before delivery). Mine was delivered with 40.
I keep mine inflated to factory specs. I didn't like the way it rode/handled with the tires pumped all the way up.
