Samd said:
It's not unprecedented (well during my childhood) to increase the wheel size ten percent, it makes speed adjustment pretty easy.
I know it's not elegant, but it's simple. 34mph is 55kph.
My drive to work is 60 kph most areas. Ten percent would get me close.
Have you priced wheels at a junkyard these days? I paid $50 for the last one I had to buy.
Two ways this would hurt:
1) There are several screens of informatics information. "Wh/mi" in the last 30 and last 5 minutes. Not to mention three different odometers, Trip A, Trip B and ODO. Then there's the maintenance minder, which is supposed to trigger every X miles (5000 or 7500, depending).
2) Computer control of the transmission, and when the motor turns on and off would be skewed by a couple MPH.
If you own a Prius, get some Bridgestone Ecopia tires in the OEM size (Costco has 'em in stock, Sam's Club won't), very slightly overinflate (1 or 2 psi), and enjoy the extra 2-2.5mpg AND having your Prius work correctly. (ref: Priuschat forums and personal experience) I went back with new versions of the OEM tire that came on the car and saw 1 mpg improvement: the tires the car ships with are softer than the aftermarket tire.
Even the crappy F-150 I bought from my brother "knew" tire size and had to be reprogrammed for it. He put huge tires on the truck and totally screwed up the mileage, shift points and computer control of the engine, because then it became impossible for the computer to know mileage and speed correctly.
After I swapped out for a more-accurate tire size and had the dealership put the correct value in the computer, shifting improved, engine performance improved and mileage improved 2 mpg over the measly 11 mpg I was getting. After a year's worth of efficiency improvements, I'm getting 17.8mpg out of that truck reliably. I'm hoping for 20mpg after new O2 sensors, adding a "Gotts Intake" and modifying the engine computer eeprom profile for 87 octane.
BTW: nice videos on YouTube, good work....
JKB