Re: 20" wheel calibration
Gnerally, the is a revolutions per mile set up in the vehicles pcm. They need to look up the correct rpm for the tire and put that in.
I asked my dealer the same thing and he was clueless about it. After looking at the difference between the size, it's not by much, as previously stated. I went from 17's to 20's and at 80 mph, there is about 1mph difference I think. Not enough to warrant me addressing.
2011 WK2 Wifes
2012 WK2 Mine