I get 40 or so mpg. I did get larger tires, though but basically I just have a lead foot. Too much highway. Any other leadfooters out there?
I got about 45 on my 45 mile commute until buying better tires. Now I get 43. I don't use ANY hypermile techniques. I drive the Prius like I drive any car, at the speed limit and relatively agressively in traffic. I figure that how much it saves me over my 5.3 Silverado is so good that I won't quibble about trying to get 5 or 10 more MPG. In a way, I bought the Prius for the technology - and it's a great car even if mine doesn't get 55 or 60 MPG.
As loaded down as my Prius is with networking gear, I get 40 to 42 MPG going 61 to 64 MPH. (A/C in the South seems like my other MPG limiter) Most serious hypermiling tricks seem to be effective if you have long stretches under 42 MPH, I do not.
How much larger are your tires? You know if you have larger tires, then to travel the same distance the tires will have to rotate less. Therefore the on board computer thinks you have travelled a shorter distance for the same amount of fuel use. Thus few MILES per gallon. When you have not really been getting as crappy mileage as it claims... (The larger tires might also actually get you crappier mileage too...) And being a leadfoot doesn't help either...
I'm not complaining. I know for sure the bigger primacy tires are 195/65/15(I think,) are not helping but I wanted a good set with improved handling since I travel frequently and always wind up with nails. The OEMs never left me stranded but that TPMS saved at least one tire. I was just wondering if anyone else didn't hypermile and maybe went 75-80 on the highway. I still think that 40-42 summertime driving with air on cold is good.